KR102721249B1 - Arithmetic encoder, arithmetic decoder, video encoder, video decoder, encoding method, decoding method and computer program - Google Patents

Abstract

An arithmetic encoder for encoding a plurality of symbols having symbol values is configured to derive interval size information for arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values having different adaptation time constants. The arithmetic encoder is configured to map a first state variable value, or a scaled version and/or a rounded version of the first state variable value, using a look-up table, and to map a second state variable value, or a scaled version and/or a rounded version of the second state variable value, using the look-up table, to obtain interval size information describing an interval size for arithmetic encoding of one or more symbols to be encoded. Additional arithmetic encoders, arithmetic decoders, video encoders, video decoders, encoding methods, decoding methods and computer programs based on the same and other concepts are also disclosed.

Description

Arithmetic encoder, arithmetic decoder, video encoder, video decoder, encoding method, decoding method and computer program

Embodiments according to the present invention create an arithmetic encoder.

Additional embodiments according to the present invention create an arithmetic decoder.

Additional embodiments according to the present invention create a video encoder.

Additional embodiments according to the present invention create a video decoder.

Additional embodiments according to the present invention create a method for encoding a plurality of symbols and a method for decoding a plurality of symbols.

Additional embodiments according to the present invention generate a corresponding computer program.

In general, embodiments according to the present invention generate a method for updating a context model using a finite state machine.

Arithmetic encoding and decoding has proven to be a valuable tool in encoding and decoding audio and video content, as well as in encoding other types of information, such as pictures, neural network coefficients, and so on. Embodiments of the present invention can be used for all of these applications. For example, it is possible to improve encoding efficiency by exploiting the known occurrence probabilities of binary values (e.g., symbols) within a binary sequence representing video or audio content (or other types of content). In particular, arithmetic encoding can handle the varying probabilities of "0" and "1" in an efficient manner, and can adapt to changes in probabilities in a fine-tuned manner.

However, for arithmetic encoding and decoding to achieve optimal coding efficiency, it is important to have good information about the probabilities of "0" and "1", which reflect their actual occurrence frequencies well.

In order to adapt to the probabilities of "0" and "1" (or, more generally, to adapt to the probabilities of the symbols to be encoded), the concept of adjusting the boundaries of the intervals within the (current) total range of values, to obtain interval sub-partitions (e.g., so that the total range of values is sub-partitioned into intervals associated with different binary values or groups of binary values) is commonly used.

In other words, information about the probabilities of different symbols (e.g. "0" and "1") is used to derive interval size information (or, equivalently, interval size values), which describe the width of the interval associated with a certain symbol (wherein the total interval width may vary over time, e.g. due to interval re-normalization, or depending on the encoding or decoding process).

Accordingly, there is a need for a concept for determining statistical values (e.g., state variable values) and/or range values (e.g., interval size values) for source interval sub-partitions (e.g., for sub-partitions of the total coding interval) that provides a good compromise between computational efficiency and reliability.

Embodiments according to the present invention comprise an arithmetic encoder for decoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic encoder is configured to derive interval size information (p ^k , R*p ^k ) for arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g., a sequence of binary values of 0 and 1) with different adaptation time constants (which are associated with a given context mode, indicated by an index k , for example), and wherein the arithmetic decoder obtains interval size information (e.g., p _k or R*p _k ) describing an interval size for arithmetic encoding of one or more symbols to be encoded, by deriving a first state variable value (s ^k ₁ ), or a scaled version and/or a rounded version of the first state variable value ( s ^k ₁ * a ^k ₁ ┘) is mapped using a lookup table (LUT1), and the second state variable value (s ^k ₂ ), or a scaled version and/or a rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is configured to map using a lookup table (LUT1).

This embodiment according to the present invention is based on the idea that interval size information can be obtained with good reliability if a lookup-table-based mapping is applied to state variable values associated with different adaptation time constants. In other words, by applying the same lookup table to two state variable values describing statistics (e.g. symbol probabilities) at different time scales, the interval size information can be obtained in an efficient manner (since only one lookup table is needed) but also with good reliability (since statistics at different time scales can be used to determine the interval size information). Mapping the state variable values using the lookup table can be considered as an important intermediate step in deriving the interval size information based on the state variable values. Optionally, one or more additional mappings and/or combinations of mapping results may follow the lookup-table-based mapping of the first and second state variable values in deriving the interval size information. Optionally, the probability values can be obtained as intermediate quantities using a lookup-table-based mapping of the first state variable values and the second state variable values. Furthermore, other concepts are possible for deriving the interval size information from the result of the lookup-table-based mapping of the first state variable values and from the result of the lookup-table-based mapping of the second state variable values.

In conclusion, this embodiment according to the present invention provides a technique for deriving interval size information based on a first state variable value and a second state variable value, using (at least) two lookup-table-based mappings. Accordingly, state variable values associated with different adaptation time constants can be mapped individually, but using the same mapping rule (defined by the lookup table), so that the resource requirement for determining the interval size information is kept reasonably small, but still allows taking into account (e.g. allowing for a weighted consideration) statistics of (or statistical information about) a plurality of previously processed (e.g. encoded or decoded) symbols obtained with the different adaptation time constants or the statistics calculations.

In a preferred embodiment, the arithmetic encoder comprises: a scaled version and/or a rounded version of the first state variable value, or s ^k ₁ * a ^k ₁ ) is configured to map the first probability value (p _k ¹ ) using the lookup table, and the arithmetic encoder is configured to map the second state variable value, or a scaled version and/or a rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is configured to map the first probability value (p _k ^{2 ) to a second probability value (p k 2} ) using the lookup table, and the arithmetic encoder is configured to obtain a combined probability value (pk] using the first probability value and the second probability value (e.g., using weighted summation or weighted averaging).

Using this concept, a combined probability value describing a symbol probability (e.g., the probability of a "1" symbol or the probability of a "0" symbol) can be easily derived based on the first state variable value and based on the second state variable value. For example, a first state variable value that follows a previously processed (e.g., encoded or decoded) symbol with a first agility can be mapped to the first probability value, and a second state variable value that follows a previously processed (e.g., encoded or decoded) symbol with a second agility can be efficiently mapped to the second probability value. Therefore, the tendency of previously processed symbols to occur at different time scales can be taken into account, and it is still possible to derive a combined probability value in a very efficient manner. The first and second state variable values can follow the tendencies of previously processed symbols with different adaptation time constants, and mapping the state variable values to "partial" probability values (the first probability value and the second probability value) contributing to the combined probability value can be done in a very resource-efficient manner using the concepts mentioned above.

In a preferred embodiment, the arithmetic encoder is configured to change the state variable value in a first direction (e.g., to become a larger positive number) if the symbol to be encoded has a first value (e.g., "1"), and to change the state variable value in a second direction (e.g., to become a larger negative number) if the symbol to be encoded has a second value different from the first value (e.g., "0") (e.g., so that the state variable value can have both positive and negative values), and the arithmetic encoder is configured to determine which lookup-table entry to evaluate depends on the ^absolute value of the individual state variable value ( _e.g. , _depends on a scaled and rounded version of the absolute value of the _state ^variable value ⁾ (e.g., depends on a scaled and rounded version of the absolute value of the state variable value).

The efficiency of this concept can be further improved by using state variable values that can have positive and negative values (e.g., depending on the history of previously processed symbols, and, e.g., in a symmetrical manner with respect to previously processed opposite symbols), and by selecting entries in the lookup table based on the absolute value of the individual state variable values. There is no longer a need to have a dedicated entry in the lookup table for each possible value (or quantized value) of the state variable value. Rather, it is possible to use an entry in the lookup table redundantly for both a positive state variable value and a corresponding negative state variable value (i.e., an "inverse" state variable value with the same absolute value but opposite sign). As a result, the number of entries in the lookup table can be kept small, and the "symmetry" of the determination of interval size information for opposite previously processed symbols can be exploited.

In a preferred embodiment, the arithmetic encoder, if the first state variable value has a first sign (e.g., a positive sign), sets the first probability value (p _k ¹ ) to a value provided by the lookup table (e.g., is configured to set the first probability value (p _k ¹ ) to a value obtained by subtracting a value provided by the lookup table from a predetermined value (e.g., 1), if the first state variable value has a second sign (e.g., a negative sign), (e.g., It is configured to set (as shown).

Using this mechanism, the number of entries in the lookup table can be kept small (e.g., because the entries in the lookup table are selected based on the absolute value of the individual state variable values), but it is still possible to obtain "complimentary" probability values for the opposite sign of the individual state variable values. Therefore, a high level of resource-efficiency and low computational complexity is obtained for determining the probability values.

In a preferred embodiment, the arithmetic encoder is configured to determine two or more probability values p ^k _i according to:

Here, LUT1 is a lookup table containing probability values; . is the floor operator; s ^k _i is the i-th state variable value; a ^k _i is a weight associated with the i-th state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

It was found that these calculations are computationally efficient and keep resource requirements reasonably low.

In a preferred embodiment, the arithmetic encoder is configured to determine two or more probability values p ^k _i according to

Here, LUT1 is a lookup table containing probability values; . is the floor operator; s ^k _i is the i-th state variable value; a ^k _i is a weight associated with the i-th state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

It has been found that such computations, depending on the actual numerical representation, are advantageous in some situations. In particular, the floor operator is applied to the same operands regardless of the sign of the state variable values. In particular, there is no need to remove the sign of the operands of the floor operator, thus saving complexity in some computations. Rather, negation is applied only to the result of the floor operator, which is typically an integer value. Accordingly, the complexity for applying the negation operator is particularly small. In other words, the concept as described herein also entails particularly low complexity.

In a preferred embodiment, the arithmetic encoder is configured to obtain a combined probability value p ^k depending on a plurality of probability values p ^k _i according to:

Here, N is the number of probability values considered (and can be equal to the number of state variable values considered); b ^k _i are weights (e.g., weighting factors controlling the influence of individual state variable values on the combined probability value) (wherein b ^k _i are preferably integer-valued potencies of 2, and the ratio between two different b ^k _i is preferably an integer-valued potency of 2).

By applying different weights to the obtained probability values based on different state variable values, different influences of short-term statistics and long-term statistics on the combined probability values can be considered, and a particularly meaningful combined probability value can be obtained.

In a preferred embodiment, the arithmetic encoder comprises: a scaled version and/or a rounded version of the first state variable value, or s ^k ₁ * a ^k ₁ ) is configured to map a first subinterval width value (R*p k 1 ) using a two-dimensional lookup table, the entry of which depends on the first state variable value (e.g., using a probability index i, for example, to determine the first lookup table entry coordinate) and on coding interval size information (e.g., an index j derived from R or R) describing the size of a coding interval of an arithmetic encoding prior to encoding of a symbol (e.g. ^, to determine the second lookup table coordinate), wherein the arithmetic encoder is configured to map the second state variable value, or a scaled version and _/ or a rounded version of the second state variable value ( s ^k ₁ * a ^k ₁ ) is configured to map a second subinterval width value (R*p k 2 ) using a two-dimensional lookup table, the entry of which depends on the second state variable value (e.g., to determine the first lookup table entry coordinate) and is addressed depending on coding interval size information (e.g., _R ) describing the size of a coding interval of an arithmetic encoding prior to encoding of a symbol (e.g., to determine the second ^lookup table coordinate), wherein the arithmetic encoder is configured to obtain a combined subinterval width value using the first subinterval width value and the second subinterval width value (e.g., using weighted summation or weighted averaging).

By using such a two-dimensional lookup table reflecting the multiplication of a plurality of different probability values and a plurality of different interval size values, the computational complexity can be reduced, because the multiplication operations can be saved. For example, one of the two indices (the row index and the column index) designating an entry of the two-dimensional lookup table is determined by the individual state variable value (or a scaled and/or rounded version thereof), and the second index is determined by the current (total) coding interval size. Therefore, based on the first index and the second index, an element (entry) of the two-dimensional lookup table can be uniquely identified, and the identified element typically reflects the product of the probability value associated with the individual state variable value and the coding interval size associated with the second table index. As a result, in some cases, the execution of the multiplication operation can be saved by consuming some memory, which may be read-only memory, for the two-dimensional lookup table, which can be computationally beneficial from a resource perspective and also from an energy consumption perspective.

In a preferred embodiment of the arithmetic encoder, the two-dimensional lookup table comprises: a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ; ) comprising a first 1-dimensional vector entry (forming a one-dimensional lookup table) containing probability values for different value intervals of the value domain, and a second 1-dimensional vector ( comprising a quantization level for the coding interval size information) ) can be expressed as a dyadic product between entries.

By using this three-dimensional lookup table, the multiplication operation between different pairs of probability values and coding interval sizes can be reflected by the table. Accordingly, by selecting appropriate elements of the two-dimensional lookup table, the execution of the multiplication operation can be saved. Furthermore, the entries of the two-dimensional lookup table can be obtained in a very simple manner using this approach.

In a preferred embodiment of the arithmetic encoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a base lookup table (Base TabLPS), a first group (or block; e.g., "upper half") of the elements of the two-dimensional lookup-table are identical to the elements of the base lookup-table or are rounded versions of the elements of the base lookup-table, and a second group (or block; e.g., "lower half") of the elements of the two-dimensional lookup-table are scaled versions and rounded versions of the elements of the base lookup-table.

By using this approach, an approximately exponential growth or decay of elements of a two-dimensional lookup table can be obtained. For example, by defining the elements of the two-dimensional lookup table such that the second group of elements of the two-dimensional lookup table are substantially (for example, except for deviations caused by rounding) scaled versions of the elements of the first group of elements of the two-dimensional lookup table, a highly uniform two-dimensional lookup table can be obtained. It should also be noted that it is easy to obtain elements of a two-dimensional lookup table by using this approach.

In a preferred embodiment of the arithmetic encoder, the second group of elements of the two-dimensional lookup-table are right-shifted versions of the elements of the base lookup table.

By using this approach, elements of a two-dimensional lookup table can be obtained in a particularly efficient manner, because the right-shift operation can be performed very easily. In addition, the right-shift operation allows for proper scaling and also allows rounding operations to be performed in a very efficient manner.

In a preferred embodiment of the arithmetic encoder, the probability indices (Qp ₂ (p _LPS ) or i)) determine whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated, and a first range (e.g. between 0 and -1) of the probability indices (which are obtained, for example, by quantizing the probability values, for example p _LPS ) is associated with elements of the first group of elements, and a second range (e.g. greater than or equal to μ) of the probability indices (which are obtained, for example, by quantizing the probability values, for example p _LPS , for example using a quantization function Qp2(.) ) is associated with elements of the second group of elements.

By using this concept, the distinction whether an element of a first group of elements or an element of a second group of elements should be used can be made, for example, based on a probability index which can be based on individual state variable values. For example, a probability index (which can be defined, for example, by the probability of the least probable symbol, or by an integer index value) can be derived, for example, using a mapping based on individual state variable values. For example, a first probability value obtained using a mapping of the first state variable value, or a second probability value obtained using a mapping of the second state variable value, can be used to determine which element of the two-dimensional lookup table should be evaluated (and, in particular, whether an element of the first group of elements of the two-dimensional lookup table or an element of the second group of elements of the two-dimensional lookup table should be evaluated).

Furthermore, using this concept, it is possible to determine individual elements of a two-dimensional lookup table "on the fly" based on a base lookup table whose number of elements is smaller than the number of table elements that can be addressed by the probability index and the coding interval size index.

In a preferred embodiment of the arithmetic encoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes the extension of the base lookup table in the first direction) and the interval magnitude index (e.g., based on the interval magnitude information (R), which can be obtained, for example, using a quantization operation Qr2(.); for example, j) determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table.

By using this concept, an appropriate element of the base lookup table can be selected even if the number of probability index values for which the base lookup table can be extended in the first direction is smaller than the number of possible probability index values. By evaluating the remainder of the division between the probability index and the first magnitude value that can describe the extension of the base lookup table in the first direction, an element of the base lookup table can be reused for two or more different probability index values (which can differ, for example, by the first magnitude value). As a result, an entry of the base lookup table can be used twice, for example, using different scaling, for two probability index values that differ by the first magnitude value. Accordingly, it can be exploited that a two-dimensional lookup table typically describes an evolution over the probability index values, where the evolution within the second range of probability index values is a scaled version (for example, excluding rounding effects) of the evolution within the first range of probability index values.

In a preferred embodiment, the arithmetic encoder is configured to obtain elements of a two-dimensional lookup table (RangTabLPS) according to:

RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j), i/μ );

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., describing the current coding interval size); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

By using this approach, interval size information, which can be specified by the result of a scaling function or a scaling operation, can be obtained in a particularly memory-efficient manner. For example, the "BaseTabLPS" lookup table can be small, because its first dimension μ is typically smaller than the range of values of the table index t associated with the probability information, and its second dimension λ can be equal to the number of possible different interval sizes described by the interval size information. Furthermore, the scaling function can be implemented in a particularly efficient manner, because the number of different scaling factors specified by the floor-operation of the quotient of t and μ is relatively small. For example, if the range of the division between t and μ is between 0 and a maximum value less than 2, only two different scaling operations can be performed. For example, there may be only two, three or four different scaling options (depending on the quotient between t and μ), and these scaling options can be efficiently implemented using only a few predetermined values of multiplication, or even only transition operations.

In a preferred embodiment of the arithmetic encoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a probability table (probTabLPS), the probability table describing interval sizes for a set of a plurality of probability values (e.g. represented by an index i) and for a given (reference) coding interval size, and the elements of the two-dimensional lookup-table for probability values not included in the set of the plurality of probability values and/or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling.

By using this approach, it can be exploited that different interval sizes are often related to each other by scaling that depends on the difference between the associated probability values and/or the difference between the associated coding interval sizes. In other words, if the two-dimensional lookup table does not contain an element that is tailored to the currently considered probability value and/or the currently considered coding interval size, an appropriate interval size can still be obtained and the other elements of the two-dimensional lookup table are scaled accordingly (e.g., scaled depending on the currently considered probability value and/or depending on the currently considered coding interval size).

In a preferred embodiment of the arithmetic encoder, the elements of said two-dimensional lookup-table are obtained using a first scaling (multiplication) of a selected element (probTabLPS[i%μ]) of said probability table depending on the coding interval size R, and a second scaling of the result of said first scaling depending on whether the element associated with the current probability value (indicated by the index i) is included in the set of probability values (e.g. depending on whether the current probability falls within the range of probability values covered by the probability table).

Accordingly, elements of the two-dimensional lookup table can be "quickly" obtained using appropriate entries of the probability table and using appropriate scaling, where the "probability table" being evaluated is typically substantially smaller than the two-dimensional lookup table. In other words, appropriate elements of the probability table are selected and scaled based on two indices addressing the elements of the two-dimensional lookup table. However, in many cases this concept provides an improved compromise between memory requirements and computational complexity.

In a preferred embodiment of the arithmetic encoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an expansion of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

By using this concept, a small probability table can be used, which represents the interval sizes within a (relatively small) part of the two-dimensional grid of probability indices and coding interval size indices, thereby saving memory space. Then, by the aforementioned selection of elements of the probability table and also by the aforementioned doubling scaling of the selected elements of the probability table, appropriate interval size information can be obtained.

In a preferred embodiment, the arithmetic encoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (or the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

By using this concept to obtain suitable elements of a two-dimensional lookup table, which can represent or be identical to the interval size information, a very good compromise between memory requirements and computational complexity can be obtained. The table "probTabLPS" can be, for example, a one-dimensional table, where the number of elements of said table can be smaller than the number of different possible values of the table index t . However, by scaling the product of the selected elements of the probability table (probTabLPS) and a scaling factor Qr ₂ (R) which depends on the interval size R, a good accuracy can be reached, and any possible round-off errors can be kept reasonably small. Furthermore, since the scaling operates on integer values obtained by the "floor" operator, an efficient scaling concept can be used, which can be specified for example by integer multiplication or integer division or bit shift operations. Therefore, the computational load is actually reduced.

In a preferred embodiment, the arithmetic encoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (or the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

This approach to obtaining interval size information turns out to be particularly efficient and provides high-quality results for the interval size information (which is obtained as a result of the first and second scaling).

In a preferred embodiment of the arithmetic encoder, the remainder of the division between a probability index (e.g. i; e.g. representing the current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes the extension of the probability table) is i%μ ) determines which element of said probability table is scaled in said first scaling; and/or an integer division result () of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

By selecting elements of the probability table (which may be a one-dimensional probability table) based on the division remainder mentioned above, the fact that the interval sizes are substantially similar within different ranges of the probability indices, except for the scaling, can be exploited. Accordingly, the probability table reflects only values within a single range of the probability indices, and the interval size values for the other ranges of the probability indices are obtained using the first scaling. In order to obtain appropriate interval size information, the second scaling adapts the values represented by the probability table, or the values obtained using the first scaling based thereon, to the coding interval sizes.

As a result, a good compromise between memory consumption, computational complexity and accuracy can be obtained, whereby, for example, division remainders and integer division results can be obtained in a computationally very simple manner, provided that the first magnitude value is chosen appropriately (e.g., to have a potency of 2).

In a preferred embodiment, the arithmetic encoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size; Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

These computational rules implement the aforementioned concepts in a very efficient way.

In a preferred embodiment of the arithmetic encoder, the two-dimensional lookup table comprises: a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ; ) comprising a first 1-dimensional vector entry (forming a one-dimensional lookup table) containing probability values for different value intervals of the value domain, and a second 1-dimensional vector ( comprising a quantization level for the coding interval size information) ) can be expressed as a dyadic product between entries.

Such a two-dimensional lookup table can be advantageously used for efficient derivation of interval size information depending on state variable values and depending on coding interval size information. A lookup operation within the two-dimensional lookup table corresponds to mapping a state variable value to a probability value and also to a multiplication of the obtained probability value and the coding interval size. Therefore, it becomes very easy to obtain interval size information which can be identical to a selected entry of the two-dimensional lookup table, wherein individual elements of the two-dimensional lookup table can be selected depending on individual state variable values and depending on coding interval size information (wherein the individual state variable value can determine the first index of an element of the two-dimensional lookup table and the coding interval size information can determine the second index).

In a preferred embodiment, the arithmetic encoder comprises: a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ), the first and second subinterval width values (R*p ^k ) are obtained from the first and second state variable values (s _k ) or the scaled versions and/or rounded versions of the first and second state variable values ( s ^k ₂ * a ^k ₂ ), the first state variable value and the second state variable value, or the scaled version and/or rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ) is mapped to first and second probability values using a one-dimensional lookup table (LUT4) entry including probability values for different value intervals of the value domain for the symbol, and quantizes coding interval size information (R) describing a size of a coding interval of the arithmetic encoding prior to encoding of a symbol into a quantization level, and in one aspect, determines a product of the first and second probability values and the quantization level (by looking up or multiplying pre-computed products), and obtains a combined subinterval width value by using the first subinterval width value and the second subinterval width value (for example, by using a weighted summation or a weighted average), thereby calculating the combined subinterval width value.

It has been found that using this approach is very efficient even in certain situations. By deriving the first sub-interval width value based only on the first state value (without considering the second state value), and by computing the second sub-interval width value based only on the second state variable value (without considering the first state variable value), the substantially separate processing of the state variable values obtained using different adaptation time constants is maintained almost throughout the entire processing. Only in the last stage are the first and second sub-interval width values combined to obtain the combined sub-interval width value, which entails high precision and avoids degradations that would occur in some situations if the first and second state variable values were combined at too early a stage.

In a preferred embodiment, the arithmetic encoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

This concept is particularly easy to implement, because logical right transitions require minimal computational resources.

In a preferred embodiment, the arithmetic encoder comprises: coding interval size information Quantizing it is configured to perform by, and hereby , and is a parameter.

It was also discovered that this quantization can be implemented very easily. In particular, the parameter , and If is chosen to be an integer value (or an integer value greater than 1), the computational effort is greatly reduced.

In a preferred embodiment of the arithmetic encoder, an entry of the one-dimensional lookup table comprises a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value. s ^k * a ^k ) monotonically decreases as the value of increases.

It has been shown that using monotonically decreasing entries in a one-dimensional lookup table gives good results for interval size information.

In a preferred embodiment of the arithmetic encoder, the first state variable value and the second state variable value, or scaled versions and/or rounded versions of the first state variable value and the second state variable value ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

This equal sizing of the value intervals allows for simple quantization. Furthermore, the equal sizing of the value intervals allows for the elements of the lookup table to be determined on-the-fly with reasonable effort.

In a preferred embodiment of the arithmetic encoder, the first state variable value and the second state variable value, or scaled versions and/or rounded versions of the first state variable value and the second state variable value ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

This monotonic decrease in the entries of a one-dimensional lookup table allows us to represent exponential decay with good accuracy.

An embodiment according to the present invention comprises an arithmetic encoder for encoding a plurality of symbols having symbol values (e.g. binary values), wherein the arithmetic encoder is configured to derive interval size information (p k , R*p k ) for arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g. sequences of binary values 0 and 1) with different adaptation time constants (which are associated with a given context mode, indicated for example by an index ^k ), wherein the arithmetic encoder is configured to derive a combined state ^{variable value (s k} ₎ ⁽ which may be for example a weighted sum of the state variable values), based on the plurality of (individual) state variable values (s i _k ), wherein the arithmetic encoder comprises interval size information (e.g. p _k or R*p ) describing an interval size for the arithmetic encoding of one or more symbols to be encoded. To obtain the combined state variable values (s _k ), or scaled versions and/or rounded versions of the combined state _variable values ( s ^k ₂ * a ^k ₂ ) is configured to map using a lookup table.

This embodiment according to the present invention is based on the idea that high efficiency is obtained in determining interval size information if the combined state variable values are determined before the mapping is performed using the lookup table. Accordingly, there is no longer a need to perform separate lookup-table lookups using two (or more) state variable values. Rather, a single table lookup may suffice for determining the interval size information. In particular, it has been found that combining the first state variable value and the second state variable value before performing the lookup-table lookup does not seriously degrade the interval size information in many situations.

In a preferred embodiment, the arithmetic encoder is configured to determine a weighted sum of the state variable values to obtain the combined state variable values.

It was found that computing the weighted sum of state variable values is an efficient way to determine the combined state variable value, and is also well suited to taking into account the different relevance of two state variable values caused by different adaptation time constants used in deriving the state variable values.

In a preferred embodiment, the arithmetic encoder comprises a state variable value (s _k ) to obtain the combined state variable value (s k ). ) and associated weight values ( ) is the rounded value obtained by rounding the product of ) is configured to determine the sum of the two.

It has been found that rounding the scaled values before performing the summation leads to particularly meaningful results. Negligible contributions of one of the state variable values are removed by the rounding and do not affect the combined state variable value. Thus, highly reliable results can be obtained, and the combined state variable value typically takes integer values, which are well suited to serve as indices for selecting elements of a lookup table.

In a preferred embodiment, the arithmetic encoder is configured to determine the combined state variable values s _k according to:

Here, s ^k ₂ is the state variable value, N is the number of state variable values considered,

Here . is a floor operator, and d ^k _i is a weight associated with the state variable values (e.g., a weighting factor controlling the influence of an individual state variable value on the combined state variable value) (wherein d ^k _i is a potential, preferably integer-valued, of 2, and the ratio between two different d ^k _i is preferably an integer-valued potential of 2) (wherein the ratio between two different d ^k _i is preferably greater than or equal to 8).

This concept of deriving combined state variable values entails very meaningful combined state variable values, as explained earlier.

In a preferred embodiment, the arithmetic encoder is configured to change the state variable value in a first direction (e.g., to become a larger positive number) if the symbol to be encoded has a first value (e.g., "1"), and to change the state variable value in a second direction (e.g., to become a larger negative number) if the symbol to be encoded has a second value different from the first value (e.g., "0") (e.g., so that the state variable value can have both positive and negative values), and the arithmetic encoder is configured to determine which entry of the lookup-table to be evaluated depends on the absolute value of the combined state variable value (e.g., depends on a scaled and rounded version of the absolute value of the combined state variable value) (e.g., depends on a scaled and rounded version of the absolute value of the combined state variable value) depending on the absolute value of the combined state variable value (s _k ⁱ if _{s k} ^{i >} 0, otherwise -s k i ).

This concept of determining state variable values (e.g., determining a first state variable value and a second state variable value) entails the same advantages as when separate mappings of the first state variable value and the second state variable value are used.

In a preferred embodiment, the arithmetic encoder is configured to, if the associated state variable value has a first sign (e.g., a positive sign), assign the probability value (p ^k ) to a value provided by the lookup table (e.g., ), and the arithmetic encoder is configured to set the probability value (p ^k ) to a value obtained by subtracting a value provided by the lookup table from a predetermined value (e.g., 1), if the combined state variable value has a second sign (e.g., a negative sign), (e.g., It is configured to set (as shown).

This notion of mapping a combined state variable value to a probability value is efficient, because the size of the lookup table can be reduced. In particular, the number of elements in the lookup table can be reduced, because the same element in the lookup table is associated with a given positive combined state variable value and with a negative version of the given (positive) combined state variable value. In other words, in the given notion, the absolute value of the combined state variable value determines which element of the lookup table is evaluated to provide a probability value.

However, the sign of the combined state variable value is still considered in a proper and efficient manner by setting the probability value to a value provided by the lookup table or to a value obtained by subtracting the value provided by the lookup table from a predetermined value, depending on the sign. Accordingly, meaningful probability values can be obtained with low computational complexity based on the combined state value.

In a preferred embodiment, the arithmetic encoder is configured to determine the combined probability value p _k according to:

Here, LUT2 is a lookup table containing probability values; . is a floor operator; s ^k is a combined state variable value; a ^k is a weight associated with the combined state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

This concept of determining a combined probability value based on the combined state variable values s _k implements the idea outlined above in a computationally highly efficient manner.

In a preferred embodiment, the arithmetic encoder is configured to determine the combined probability value p _k according to:

Here, LUT2 is a lookup table containing probability values; . is a floor operator; s ^k is a combined state variable value; a ^k is a weight associated with the combined state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

In this concept, there is no absolute value computation of the scaled combined state variable values s _k . Rather, there is only a "floor" operation, which is applied to the scaled ("weighted") combined state variable values, which in some circumstances can be implemented with less effort than the absolute value formation. Negation applies only to integer values, which are obtained by downward-rounding (the floor operator) of the weighted combined state variable values. However, negating an integer value is typically less complex than negating a fractional value or a value in a floating point representation. Accordingly, the concepts discussed herein may help reduce the complexity in some circumstances.

In a preferred embodiment, the arithmetic encoder comprises: a scaled version and/or a rounded version of the combined state variable value, or s ^k * a ^k ) is configured to map subinterval width values (R*p k ) using a two-dimensional lookup table, the entries of which depend on the combined state variable values (e.g., to determine the first lookup table entry coordinates) and on coding interval size information (e.g., R) describing the size of a coding interval of the arithmetic encoding prior to encoding of the symbol (e.g., to determine the second lookup ^table entry coordinates).

By using this concept, the mapping of the combined state variable values to the combined probability values and the multiplication of the combined probability values by the coding interval size can be integrated into a single lookup table lookup operation. Thus, a two-dimensional lookup table is required, but the multiplication operation is saved. The entries of the two-dimensional lookup table can be precomputed, so that the integration overhead at runtime is kept very low. Rather, the first table index can be determined based on the combined state variable values, or scaled and/or rounded versions of the combined state variable values, and the second table index can be determined based on the coding interval size information (e.g., using rounding or quantization). The first stage index and the second state index can uniquely designate elements of the two-dimensional lookup table, and the designated elements of the two-dimensional lookup table can be used as subinterval width values (or as interval size information). Thus, a very efficient concept is obtained that saves computational complexity when sufficient memory for the lookup table is available.

In a preferred embodiment of the arithmetic encoder, the two-dimensional lookup table comprises: the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values; s ^k * a ^k ; ) contains probability values for different value intervals in the value domain, the first 1-dimensional vector entry ( ; forming a one-dimensional lookup table), and a second one-dimensional vector ( comprising a quantization level for the coding interval size information ) can be expressed as a dyadic product between entries.

These two-dimensional lookup tables provide very good results. In particular, each element of these two-dimensional lookup tables represents an individual probability value associated with a combined state variable value and a multiplication of the coding interval size. Therefore, the two-dimensional lookup table described herein eliminates the need for multiplication, which can be considered very resource-efficient.

In a preferred embodiment of the arithmetic encoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a base lookup table (Base TabLPS), a first group (or block; e.g., "upper half") of the elements of the two-dimensional lookup-table are identical to the elements of the base lookup-table or are rounded versions of the elements of the base lookup-table, and a second group (or block; e.g., "lower half") of the elements of the two-dimensional lookup-table are scaled versions and rounded versions of the elements of the base lookup-table.

By defining the elements of the two-dimensional lookup table based on the base lookup table, the two-dimensional lookup table can be generated in a very simple manner. Furthermore, since the second group of elements of the two-dimensional lookup table are scaled versions and rounded versions of the elements of the base lookup table (whereas the elements of the first group of elements of the two-dimensional lookup table are either identical to the elements of the base lookup table or are rounded versions of the elements of the base lookup table), the exponential evolution of the elements within the rows or columns of the two-dimensional lookup table is well reflected. By using the concept that the second block of elements of the two-dimensional lookup table is effectively (excluding the rounding effect) a scaled version of the first block of elements of the two-dimensional lookup table, it becomes possible to reflect appropriate properties for mapping the combined state variable values to the interval size information.

In a preferred embodiment of the arithmetic encoder, the second group of elements of the two-dimensional lookup-table are right-shifted versions of the elements of the base lookup table.

Then, entries (elements) of a two-dimensional lookup table can be created simply.

It was discovered that right-shifting elements of the base lookup table is a very efficient concept for combining scaling and rounding operations.

In a preferred embodiment of the arithmetic encoder, the probability indices (Qp ₂ (p _LPS ) or i)) determine whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated, and a first range (e.g. between 0 and μ-1) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS ) is associated with elements of the first group of elements, and a second range (e.g. greater than or equal to μ) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS , using, for example, a quantization function Qp2(.) ) is associated with elements of the second group of elements.

By using a probability index which can be derived directly from the combined state variable values (without using probability values as intermediate quantities) or derived using the combined probability values based on the combined state variable values, the selection of elements of the two-dimensional lookup table can be made very efficiently. Furthermore, the probability index is used to switch between using elements of the first group of elements and elements of the second group of elements, which allows for efficient and fast determination of elements of the two-dimensional lookup table.

In a preferred embodiment of the arithmetic encoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes the extension of the base lookup table in the first direction) and the interval magnitude index (e.g., based on the interval magnitude information (R), which can be obtained, for example, using a quantization operation Qr2(.); for example, j) determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table.

In a preferred embodiment, the arithmetic encoder is configured to obtain elements of a two-dimensional lookup table (RangTabLPS) according to:

RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j], i/μ )

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., describing the current coding interval size); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

By evaluating the division remainder to determine which element of the base lookup table is used to obtain an element of the two-dimensional lookup table, rapid determination of an element of the two-dimensional lookup table can be performed with very high efficiency. In particular, the fact that the two-dimensional lookup table includes two or more groups of elements based on elements of the same base lookup table can be reflected by using the division remainder to determine which element of the base lookup table is used to obtain an element of the two-dimensional lookup table. In other words, the periodic relationship between the elements of the two-dimensional lookup table and the elements of the base lookup table is well reflected by considering the division remainder, because the division remainder also becomes periodic as the probability index increases.

In a preferred embodiment of the arithmetic encoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a probability table (probTabLPS), the probability table describing interval sizes for a set of a plurality of probability values (e.g. represented by an index i) and for a given (reference) coding interval size, and the elements of the two-dimensional lookup-table for probability values not included in the set of the plurality of probability values and/or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling.

These concepts are based on the same considerations as the corresponding concepts described in the case of discrete mappings of state variable values.

In a preferred embodiment of the arithmetic encoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a probability table (probTabLPS), the probability table describing interval sizes for a set of a plurality of probability values (e.g. represented by an index i) and for a given (reference) coding interval size, and the elements of the two-dimensional lookup-table for probability values not included in the set of the plurality of probability values and/or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling.

It has been found that such a fast determination of the elements of the two-dimensional lookup table involves particularly high resource efficiency. Furthermore, it should be noted that what has been said for the corresponding algorithms used in the context of separate mappings of the first and second state variable values also applies. By using a probability table that is typically smaller (e.g. contains fewer elements) than the two-dimensional lookup table as a basis for the determination of the elements of the two-dimensional lookup table, very high efficiency can be achieved. For example, the probability table can represent the mapping of different probability values and different (quantized) coding interval sizes over a large range, and thus can help to avoid multiplications that fall outside the scope of simple scaling (wherein the "simple" scaling can be implemented, for example, using transition operations).

The elements of the two-dimensional lookup table for one or more probability values that are not included in the set of multiple probability values and for one or more coding interval sizes different from the given coding interval size are derived from the probability table using scaling. Accordingly, it is sufficient to have a very small probability table, which may for example only contain one row or one column. Therefore, the number of elements of the probability table can be much smaller than the number of different possible probability values (i.e. smaller than the number of different possible probability indices of the two-dimensional lookup table). Furthermore, it should be noted that the scaling depends on the probability values and/or on the coding interval size. The scaling can be performed using, for example, very simple mechanisms, for example, bit-shift operations, if the size of the probability table is appropriately chosen. Such "simple" scaling operations based on bit-shift operations require much less computational resources compared to "normal" multiplication with arbitrary variable operands (which are for example different in potency of 2).

In a preferred embodiment of the arithmetic encoder, the elements of said two-dimensional lookup-table are obtained using a first scaling (multiplication) of a selected element (probTabLPS[i%μ]) of said probability table depending on the coding interval size R, and a second scaling of the result of said first scaling depending on whether the element associated with the current probability value (indicated by the index i) is included in the set of probability values (e.g. depending on whether the current probability falls within the range of probability values covered by the probability table).

It has been found that such computations of elements of a two-dimensional lookup table are particularly efficient. Furthermore, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of the first and second state variable values.

In a preferred embodiment of the arithmetic encoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or wherein the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment, the arithmetic encoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (or the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, an element of the two-dimensional lookup-table is obtained by using a first scaling of a selected element of the probability table (probTabLPS[i%μ]) depending on whether the element associated with the current probability value (indicated by index i) is included in the set of probability values (e.g. depending on whether the current probability value is within the range of probability values covered by the probability table), and using a second scaling of the result of the first scaling depending on the coding interval size (R).

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, the remainder of the division between a probability index (e.g. i; e.g. representing the current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes the extension of the probability table) is i%μ ) determines which element of said probability table is scaled in said first scaling; and/or an integer division result () of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In connection with this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of the first state variable values and the second state variable values, wherein combined state variable values or combined probability values are used instead of the individual individual state variable values or individual probability values.

In a preferred embodiment, the arithmetic encoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size; Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In connection with this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of the first state variable value and the second state variable value, wherein the combined state variable value replaces the individual state variable values, and the combined probability value replaces the individual probability values.

In a preferred embodiment, the arithmetic encoder comprises: a scaled version and/or a rounded version of the combined state variable value, or s ^k * a ^k ), the subinterval width value (R*p ^k ), the combined state variable value (s _k ) or the scaled version and/or rounded version of the combined state variable value ( s ^k * a ^k ; ), the combined state variable values, or a scaled version and/or rounded version of the combined state variable values ( s ^k * a ^k ; ) is configured to map a combined probability value using a one-dimensional lookup table (LUT4) entry including probability values for different value intervals of the value domain, and to quantize coding interval size information (e.g., R) describing a size of a coding interval of the arithmetic encoding prior to encoding of a symbol into a quantization level, and to compute the product of the combined probability value and the quantization level (by looking up pre-computed products or by multiplication).

In connection with this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of the first state variable value and the second state variable value, wherein the combined state variable value replaces the individual state variable values, and the combined probability value replaces the individual probability values.

In a preferred embodiment, the arithmetic encoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment, the arithmetic encoder comprises: coding interval size information Quantizing it is configured to perform by, and hereby , and is a parameter.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, an entry of the one-dimensional lookup table contains: a combined state variable value, or a scaled version and/or a rounded version of the combined state variable value; s ^k * a ^k ) monotonically decreases as the value of increases.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, an entry of the one-dimensional lookup table contains: a combined state variable value, or a scaled version and/or a rounded version of the combined state variable value; s ^k * a ^k ) monotonically decreases with an increasing rate.

In relation to this functionality, reference is also made to the preceding discussion of the corresponding functionality provided in the context of separate mappings of first state variable values and second state variable values.

In a preferred embodiment of the arithmetic encoder, the lookup-table specifies an exponential decay (e.g., decreasing from 0.5) (e.g., within a tolerance of +/-10% or +/-20%).

It was found that exponential decay provides a good fit for deriving interval size information based on state variable values. In addition, exponential decay can be expressed very efficiently using lookup tables, in which case even rapid determination of elements of the lookup table becomes possible with little effort.

In a preferred embodiment, the arithmetic encoder has multiple variable state values It is configured to update as follows:

Here, z is a predetermined (constant) offset value; is one or more weights; is one or more weights, and A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size, for example: go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical formula described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero), here , , , and are predetermined parameters (examples are stated above).

It has been found that such updates of state variables can be performed with high computational efficiency, where the mapping table can be precomputed. For example, the state variable values A result can be obtained in which the state variable values remain within a predetermined range (e.g., between a predetermined minimum value and a predetermined maximum value). Moreover, by using an appropriate choice of the mapping table A , a result can be obtained in which the state variable values are well adapted to the description of the statistics of previously processed (e.g., encoded or decoded) symbols. It should also be noted that the adaptation time constants of individual state variable values can be adapted by appropriately choosing the weights m and n. Therefore, the algorithm described herein is adapted to the state variable values It can be used efficiently for updates.

In a preferred embodiment, the arithmetic encoder is configured to derive by table lookup operation or by calculation.

Therefore, different concepts become possible for deriving updated state variable values.

Embodiments according to the present invention are an arithmetic encoder for encoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic encoder is configured to determine one or more state variable values (s 1 k , s ₂ ^k ) representing statistics (e.g., statistics having different adaptation time constants when there are multiple state variable values) of a plurality of previously encoded symbol values (e.g., sequences of binary values 0 and 1), and wherein the arithmetic encoder is configured to derive interval size information ( _p ^k , R*p ^k ) for arithmetic encoding of the one or more symbol ^values to be encoded based on one or more state variable values (s _i ^k ) representing statistics (e.g., statistics having different adaptation time constants when there are multiple state variable values) of a plurality of previously encoded symbol values (e.g., sequences of binary values 0 and 1) (which are associated with a given context mode denoted by k , for example), wherein the arithmetic encoder is configured to: Create an arithmetic encoder configured to update the state variable value (s ^k ₁ ) depending on the symbol to be encoded and using a lookup table (A) (e.g., after encoding the symbol to be encoded).

This embodiment according to the invention is based on the discovery that the updating of state variable values, which is used to derive interval size information for arithmetic coding (e.g. encoding or decoding), can be performed with particularly good results using lookup tables, since the use of lookup tables allows updating of state variable values which are particularly well adapted to the characteristics of the signal to be encoded or decoded. For example, it is easy to express a fine-tuned relationship between "old" state variable values and updated state variable values using lookup tables, without the need to perform extensive calculations (e.g. evaluating trigonometric or exponential or logarithmic functions, etc.). Therefore, implementing the updating of state variable values using lookup tables helps to keep the computational complexity reasonably small. Ideally, only multiplications (or simple multiplications, e.g. bit shift operations), rounding operations and additions are used in addition to lookup table lookups to obtain updated state variable values based on "old" state variable values. For example, the currently processed symbol (e.g., the symbol to be encoded or the symbol to be decoded) determines which part of a lookup-table-based mapping rule is evaluated to obtain updated state variable values, for example.

In conclusion, it was found that providing updated state variable values using a lookup table provides both high flexibility and low computational complexity.

In a preferred embodiment, the arithmetic encoder is configured to update a second state variable value (s ^k ₂ ) depending on the symbol to be encoded and using a lookup table (A) (e.g., after encoding the symbol to be encoded).

It has been found that it is advantageous to update the second state variable values using the same lookup table as was used to update the first state variable values. For example, differences that may exist in the adaptation time constants of the first and second state variable values can be taken into account, for example by using one or more scaling factors, which can be applied, for example, to select elements of the lookup table and/or to scale selected elements of the lookup table. Consequently, even if only one lookup table is used to derive two or more state variable values, the two or more state variable values can be adapted to represent different statistical properties of the processed symbol values (i.e. of the previously encoded symbol values or of the decoded symbol values).

In a preferred embodiment, the arithmetic encoder is configured to update the first state variable value and the second state variable value using different adaptation time constants.

By updating the first and second state variable values using different adaptation time constants, different statistical properties of previously processed symbols can be reflected by the state variable values. The availability of state variable values representing statistics of processed symbols with different adaptation time constants is of great help in accurately adjusting the interval size for arithmetic coding (encoding/decoding) of symbols. In addition, it has been found that lookup-table-based updating of state variable values provides very high reliability and low computational complexity.

In a preferred embodiment, the arithmetic encoder is configured to selectively increment or decrement a previous state variable value by a value determined using the lookup table, depending on whether the symbol to be encoded has a first value or a second value different from the first value.

By using this approach, the state variable values can be recursively adapted, where the symbol processed (e.g. the symbol to be encoded, or a previously encoded symbol, or a previously decoded symbol) determines the direction of change (increase or decrease) of the state variable values. On the other hand, the magnitude of the adaptation (i.e. increase or decrease) is determined by the selected lookup table entry, to which scaling can be applied. An efficient mechanism exists for updating the state variable values, which provides a high level of flexibility and is still very resource-efficient.

In a preferred embodiment, the arithmetic encoder is configured to, if the symbol to be encoded has a first value, increase a previous state variable value by a relatively larger value if the previous state variable value is negative compared to the case where the previous state variable value is positive, and the arithmetic encoder is configured to, if the symbol to be encoded has a second value different from the first value (which is obtained, for example, by appropriately selecting a look-up table), decrease the previous state variable value by a relatively larger value if the previous state variable value is positive compared to the case where the previous state variable value is negative.

By using this approach, it can be obtained that the state variable values change exponentially towards the maximum positive value and exponentially towards the minimum value. This approximation towards the (positive) maximum and towards the (negative) minimum can be done in a nearly asymptotic manner. In other words, the further the current state variable value is from the (positive) maximum, the larger the (increasing) step towards the (positive) maximum, and the further the current state variable value is from the (negative) minimum, the larger the (decreasing) step towards the (negative) minimum. Therefore, the exponential asymptotic behavior can be approximated using this notion. However, it has been found that this notion works very well for updating the state variable values. In particular, it has been found that this approach works well for the "infinite impulse response" approach for determining the state variable values.

In a preferred embodiment, the arithmetic encoder is configured to, if a symbol to be encoded has a first value, output a predetermined (e.g., fixed) offset value (z) and a previously computed first state variable value ( ), or a scaled version and/or rounded version of the previously computed first state variable value ( ) is configured to determine an index of an entry of the lookup table to be evaluated when updating the first state variable value, depending on the sum of the first and second values of the lookup table, and the arithmetic encoder is configured to determine, if the symbol to be encoded has a second value, an inverted (multiplied by -1) version of the first state variable value and a predetermined (e.g., fixed) offset value (z). ), or a scaled version and/or a rounded version thereof (an inverted version of the previously computed first state variable value). ) is configured to determine the index of an entry of the lookup table to be evaluated when updating the value of the first state variable.

By using this approach, an appropriate entry in the lookup table can be selected with reasonable effort, taking into account the symbol currently being processed. Both the previously computed state variable value and the processed (encoded or decoded) symbol determine the selection of the entry in the lookup table, and consequently, how much the updated state variable value is increased or decreased compared to the previously computed state variable value. An offset value can ensure that, for example, summing the offset value and the scaled (and possibly inverted, depending on the processed symbol) previously computed state variable value results in a valid lookup table index, since valid lookup table indices are typically non-negative. By using this concept, it becomes easy to select an appropriate lookup table index and to provide an updated state variable value efficiently.

In a preferred embodiment, the arithmetic encoder is configured to, when a symbol to be encoded has a first value, output a predetermined (e.g., fixed) offset value (z) and a previously computed second state variable value ( ), or a scaled version and/or rounded version of the previously computed second state variable value ( ) is configured to determine an index of an entry of the lookup table to be evaluated when updating the second state variable value, depending on the sum of the values of the lookup table, and the arithmetic decoder is configured to determine, if the symbol to be encoded has a second value, an offset value (z) that is predetermined (e.g., fixed) and an inverted (multiplied by -1) version of the previously computed second state variable value ( ), or a scaled version and/or rounded version thereof (an inverted version of the previously computed second state variable value). ) is configured to determine the index of an entry of the lookup table to be evaluated when updating the value of the second state variable.

This concept for updating the second state variable value is substantially identical to the concept for updating the first state variable value, whereby, for example, the same lookup table can be evaluated to save memory resources, and, for example, different scaling values can be used compared to the update of the first state variable value, thereby obtaining changed state variable value update characteristics. For example, different adaptation time constants for the first state variable value and the state variable value can be obtained by using different scaling values for the determination of the updated first state variable value and the updated second state variable value.

In a preferred embodiment, the arithmetic encoder is configured to apply a first scaling value (m k 1 ) to scale a previously computed first state variable value (s ^k ₁ ) when determining an index of an entry of the lookup table to be evaluated when updating the first state variable value, and the arithmetic encoder is configured to apply a second scaling value (m ^k ₂ ) to scale a previously computed second state variable value (s ^k ₂ ) when determining an index of an entry of the lookup table to be evaluated when updating the second state variable value, wherein the first scaling value is different from the second scaling value ( _and , preferably, the first and second scaling values are of integer potentials ^of 2, and a ratio between the first scaling value and the second scaling value is of integer potentials of 2, and the first scaling value and the second scaling value are different from each other by a factor of at least 8). (preferable).

When updating the first state variable value, by using different scaling values when determining the index of the entry of the lookup table to be evaluated, and when updating the second state variable value, by using different scaling values when determining the index of the entry of the lookup table to be evaluated, different adaptation time constants can be efficiently implemented, where the basic state variable value update algorithm and the used lookup table can be the same, and the only big difference can be the choice of the scaling value. Then, the implementation can be implemented with much saving of resources.

In a preferred embodiment, the arithmetic encoder is configured to scale a value returned by evaluation of the lookup table when updating the first state variable value using a first scaling value (e.g., n ^k ₁ ), and the arithmetic encoder is configured to scale a value returned by evaluation of the lookup table when updating the second state variable value using a second scaling value (e.g., n ^k ₂ ), wherein the first scaling value is different from the second scaling value.

Scaling the values returned by evaluating the lookup table (e.g. the selected lookup table entry) differently as described allows to efficiently implement different adaptation time constants when updating the first state variable value and the second state variable value. Furthermore, this scaling allows to use the same lookup table for updates to the first state variable value and for updates to the second state variable value, which helps to save memory resources.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

It was found that this update mechanism for state variable values can be implemented with high computational efficiency and provides reliable results.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

It has been found that this mechanism for updating state variable values can be very advantageous in some situations. In particular, this approach eliminates the need to invert floating point values, which can be computationally inefficient in some implementations. Therefore, this concept is accompanied by very good resource efficiency in some situations.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

It has been found that this concept provides particularly high computational efficiency and good accuracy even in some implementation environments.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

It has been found that this concept also brings advantages in terms of computational efficiency and reliability in some situations.

In a preferred embodiment of the arithmetic encoder, the entries of A monotonically decrease as the lookup table index increases.

By using this approach, the approximation of the state variable values towards their maximum or minimum can be monotonous and/or continuous and/or asymptotic. For example, state variables far from their respective maximum or minimum values may change relatively quickly towards their maximum or minimum values, whereas state variable values close to their respective maximum or minimum values may change relatively slowly towards said maximum or minimum values. Therefore, the aforementioned choice of entries in the lookup table allows for a smooth approximation of the maximum or minimum values, which turns out to be very useful for deriving interval size information based on one or more state variable values.

In a preferred embodiment of the arithmetic encoder, A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size (e.g. go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical formula described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero), here , , , and are predetermined parameters (examples are stated above).

It was found that this choice of lookup table A is accompanied by particularly advantageous behavior of the state variable values that are updated using said lookup table A.

In a preferred embodiment of the arithmetic encoder, the last entry of the lookup table (addressed when the first state variable value reaches a predetermined range of values extending to a maximum allowed value, or when the first state variable value exceeds a predetermined threshold value) is equal to zero.

By using the last entry of the above lookup table as 0, it is easy to avoid the updated state variable values going beyond the maximum and/or minimum values.

In a preferred embodiment, the arithmetic encoder is configured to apply a clipping operation to the updated state variable values so as to keep the updated state variable values and the clipped state variable values within a predetermined range of values.

By using this mechanism, it is easy to prevent the state variable values from going outside a predetermined range between the minimum and maximum values. Accordingly, it can be guaranteed that the state variable values have "reasonable" values.

In a preferred embodiment, the arithmetic encoder performs the clipping operation according to

It is configured to apply to the updated state variable values, where Is is the maximum allowable value for Is is the minimum allowable value for .

It was discovered that these clipping operations can be implemented in an efficient manner and that invalid state variable values are avoided.

In a preferred embodiment, the arithmetic encoder is configured to apply different scaling values for different context models (e.g., to cause at least one of the scaling values to vary between two different context models).

By using different scaling values for different context models, different statistical properties of different context models (which may be associated with different types of information and/or types of bit stream syntax elements) can be taken into account. By using different scaling values for different context models, the update process for state variable values can be easily adapted to different context models without fundamentally changing the underlying algorithm. Therefore, appropriate scaling values can be obtained in a very efficient manner.

In a preferred embodiment, the arithmetic encoder is configured to obtain interval size information as specified in one of the embodiments described above.

It was found that the concept of updating state variable values can be used in good combination with the previously mentioned concept of deriving interval size information.

An embodiment according to the present invention is an arithmetic encoder for encoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic encoder is configured to derive an interval size value (R _LPS ) for arithmetic encoding of one or more symbol values to be encoded based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g., a sequence of binary values of 0 and 1), wherein the arithmetic encoder is configured to determine the interval size value (R _LPS ) using a base lookup table (Base TabLPS), wherein the arithmetic encoder determines that if a probability index (i) (e.g., equal to i=Qp(p _LPS )) obtained based on the one or more state variable values is within a first range (e.g., less than μ), the determined interval size value is equal to an element of the base lookup table or a rounded version of an element of the base lookup table, and the probability If the index is within the second range (e.g., greater than or equal to μ), the determined interval size value is obtained by using scaling and rounding of elements of the base lookup table, thereby generating an arithmetic encoder, wherein the arithmetic encoder is configured to perform _{arithmetic encoding of one or more symbols using the interval size value (R LPS )} .

This embodiment according to the present invention is based on the fact that determining interval size values within an arithmetic encoder can be performed by using a "base lookup table" whose dimension is smaller than the number of different interval size values associated with a given current coding interval size, by reusing elements of the base lookup table, once without scaling and once with scaling. Accordingly, the fact that interval size values for arithmetic coding (encoding/decoding) associated with different ranges of state variable values are substantially different by scaling (e.g. except for some rounding effects) can be exploited. Accordingly, a relatively small "base lookup table" can be used, the entries of which are reused multiple times for different probability indices (wherein the probability indices can be derived based on the derived individual state variable values).

In conclusion, the concepts described herein enable highly efficient determination of interval size values based on the values of one or more state variables.

In a preferred embodiment, the arithmetic encoder is configured to determine the interval size value (R _LPS ) such that the determined interval size value becomes a right-shifted version of an element of the base lookup table if the probability index is within the second range.

This concept is based on the idea that the right-transition operation is computationally very efficient, and still provides reliable interval size values if the probability index is within the second range (although it is desirable that the transition operation not be applied to an element of the base lookup table if the probability index is within the first range). Consequently, the interval size values provided for "corresponding" probability indices within the first range and within the second range differ primarily by bit-transition (excluding any rounding that may be performed). This is typically true across the range of probability index values, or even across the entire "first range" (which typically includes three or more different values). Furthermore, it should be noted that the right-transition operation typically corresponds to division by a potential of 2.

In a preferred embodiment, the probability index (Qp2(p _LPS )) determines whether an element of the lookup table is provided as the interval size value (R _LPS ), or whether an element of the lookup table is scaled and rounded to obtain the interval size value (R _LPS ).

The algorithm for determining whether scaling (and optionally rounding) is applied to obtain interval size values based on the elements of a lookup table (the base lookup table) for a probability index (or, in particular, the question of whether the probability index falls within the first range or within the second range) can be kept very simple. For example, the check whether the probability index falls within the first range or within the second range can be easily performed by dividing the probability index by a predetermined value, or by comparing the probability index to one or more threshold values. Accordingly, it can be easily determined whether scaling (and optionally rounding) is performed based on the probability index. Therefore, this concept for deriving interval size values is very efficient.

In a preferred embodiment of the arithmetic encoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes an extension of the base lookup table in the first direction) and the interval magnitude index (e.g., obtained using a quantization operation Qr2(.), based on the interval magnitude information or the overall interval magnitude information (R)) determines which element of the base lookup table is used to obtain the interval magnitude information.

By selecting entries of the base lookup table depending on the division remainder and also depending on the interval size index, a two-dimensional base lookup table can be easily evaluated, where elements of the two-dimensional base lookup table can include multiplications with interval size values (which can be expressed by the interval size indexes). Therefore, by having a two-dimensional base lookup table it is possible to save multiplications with interval size values (wherein the division remainder can be used as the first table index, and the interval size index can serve as the second table index). Furthermore, using the division remainder as the first table index adapts well to the fact that elements of the base lookup table are selected cyclically as the probability index increases (since subsequent ranges of the probability indexes select a common range of the base lookup table). In conclusion, the implementation mentioned above allows very simple access to the elements of the base lookup table and helps to avoid multiplication with interval size values due to the two-dimensional nature of the base lookup table.

In a preferred embodiment, the arithmetic encoder is configured to obtain interval size values R _XPS (e.g. R _LPS ) according to:

R _XPS =Scal(BaseTabLPS[i%μ][j], i/μ )

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., total interval size information (R)); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

It has been found that this concept for determining the interval size values that constitute the interval size information is computationally highly efficient and allows the use of a relatively small base lookup table. In particular, the multiplication operation can be avoided. Furthermore, for example, if the dimension μ has a potential of 2, the division remainder operation and the division operation can also be implemented in a computationally very efficient manner. Therefore, the described concept for deriving the interval size values allows for a computationally very efficient implementation.

In a preferred embodiment, the arithmetic encoder is configured to derive an interval size value (R _LPS ) for an arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g. sequences of binary values 0 and 1) (e.g. having different adaptation time constants), which are associated with a given context mode, e.g. indicated by an index k; The arithmetic encoder is configured to determine an interval size value (R _LPS ) based on a (current) probability value derived from one or more state variable values and based on a (current) coding interval size (R), using a probability table (ProbTabLPS) (the dimension of which is smaller than the number of possible probability indices i in terms of probability indices), wherein the probability table describes interval sizes (interval size values) for a set of a plurality of probability values (e.g. for probability indices between 0 and μ-1) and for (a) given (reference) coding interval size, and the arithmetic encoder scales an element of the probability table (Prob_TabLPS) (e.g. an element selected depending on the current probability value) to determine the interval size if the current probability value is not within the set of the plurality of probability values (e.g. if the probability index associated with the current probability value is greater than or equal to μ) and/or if the current coding interval size (R) is different from the given (reference) coding interval size. is configured to obtain a value [R _LPS ); and the arithmetic encoder is configured to perform arithmetic encoding of one or more symbols using the interval size value (R _LPS ).

This concept is based on the idea that interval size values associated with different (non-overlapping) ranges of probability values (or probability indices) are substantially related (except for possible rounding effects) by a scaling operation. It should also be noted that the scaling operation can be implemented in a computationally efficient manner, for example using bit-shift operations, if the size of the lookup table (probability table) is suitably chosen. As a result, it becomes possible to derive interval size values used for arithmetic coding (encoding or decoding) with little computational effort and also using only small-sized lookup tables, which saves memory.

In a preferred embodiment, the arithmetic encoder is configured to obtain the interval size value using a first scaling of a selected element (probTabLPS[i%μ]) of the probability table depending on the (current) coding interval size R, and a second scaling of the result of the first scaling depending on whether an element associated with a current probability value (indicated by index i) is included in the set of probability values (e.g. depending on whether the current probability falls within a range of a plurality of probability values covered by the probability table).

By using two-step multiplication or scaling to obtain interval size information, a small probability table can be used. For example, the probability table can "directly" cover only a single coding interval size and a given, relatively small range of probability values (which can be expressed by a "set of multiple probability values"). Accordingly, for any other coding interval size, and for any probability value that is not included in the set of multiple probability values "directly" covered by the probability table, scaling is performed so that meaningful and reliable interval size values are obtained.

In a preferred embodiment of the arithmetic encoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an expansion of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) determines the coding interval size (R), and/or determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

Using division remainders to determine which elements of a probability are scaled helps to exploit the fact that entries in a probability table are reused cyclically (i.e., in a circular fashion) as the probability index increases. Using division remainders expresses this fact. Furthermore, division remainders can be computed with very high computational efficiency in some situations, especially when the division is done by a power of 2.

Moreover, by determining the scaling factor based on the result of integer division, it is easy to assign the scaling factor to different (adjacent) ranges of probability index values. Furthermore, the result of integer division can be computed in a computationally highly efficient manner in some situations, especially if the division is done with a potentiometer of 2.

Moreover, if the odds scaling factor is determined based on the coding interval size, the fact that the interval size value is scaled according to the coding interval size is reflected. Accordingly, the interval size value can be obtained with high efficiency and accuracy.

In a preferred embodiment, the arithmetic encoder is configured to obtain interval size values R _XPS (e.g. R _LPS ) according to:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (e.g., the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

It has been shown that such an algorithm for determining the interval size value is computationally efficient and provides good quality results. The probability table can be relatively small and the scaling function can be implemented in a computationally efficient manner, for example using one or more bit-shift operations.

In a preferred embodiment, the arithmetic encoder is configured to obtain an interval size value by using a first scaling of a selected element (probTabLPS[i%μ]) of the probability table, depending on whether an element associated with a current probability value (specified by index i) is included in the probability values (e.g. depending on whether the current probability value is within the range of probability values covered by the probability table), and using a second scaling of the result of the first scaling depending on the coding interval size (R).

In this concept, the processing order of the first scaling and the second scaling is reversed compared to the previously mentioned concepts. However, the basic considerations remain the same.

In a preferred embodiment, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of the probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value. i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ or a ^{-b i/μ} ) and/or wherein the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In this concept, the order of the first scaling and the second scaling is reversed compared to the previously mentioned concepts. However, the basic considerations remain unchanged.

In a preferred embodiment, the arithmetic encoder is configured to obtain interval size values R _XPS (e.g. R _LPS ) according to:

Here i is a table index associated with probability information; j is a table index associated with (current) interval size information; % is a division remainder operation; / is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μμ is the number of elements in the probability table (where the range of values of i is typically larger than μμ); R is an interval size (e.g., the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In this concept, the scaling order of the first scaling and the second scaling is reversed compared to the previously mentioned implementation. However, the underlying idea remains unchanged.

Hereinafter, various embodiments related to arithmetic decoding will be described. However, the ideas, considerations and details inherent in these ideas and related to arithmetic decoding are substantially the same as the ideas, considerations and details inherent in arithmetic encoding. Accordingly, the above-described descriptions also apply in a similar manner. However, the symbol value to be encoded corresponds to the symbol value to be decoded or to a previously decoded symbol, and the previously encoded symbol value corresponds to a previously decoded symbol value. Moreover, the correspondence between the encoding feature and the decoding feature will be apparent to those skilled in the art, and will also be clearly revealed by comparing the claim terms.

An embodiment according to the present invention is an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic decoder is configured to derive an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously decoded symbol values (e.g., a sequence of binary values of 0 and 1), wherein the arithmetic decoder is configured to determine the interval size value (R _LPS ) using a base lookup table (Base TabLPS), and the arithmetic encoder determines that if a probability index (i) (e.g., equal to i=Qp(p _LPS )) obtained based on the one or more state variable values is within a first range (e.g., less than μ), the determined interval size value is equal to an element of the base lookup table or a rounded value of an element of the base lookup table. An arithmetic decoder is configured to determine an interval size value (R LPS ) such that the determined interval size value is obtained by using scaling and rounding of elements of the base lookup table, if the probability index is within a second range (e.g., greater than or equal _{to μ ), and the arithmetic decoder is configured to perform arithmetic decoding of one or more symbols using the interval size value (R LPS )} .

In a preferred embodiment, the arithmetic decoder is configured to determine the interval size value (R _LPS ) such that the determined interval size value becomes a right-shifted version of an element of the base lookup table if the probability index is within the second range.

In a preferred embodiment of the arithmetic decoder, the probability index (Qp2(p _LPS )) determines whether an element of the lookup table is provided as the interval size value (R _LPS ), or whether an element of the lookup table is scaled and rounded to obtain the interval size value (R _LPS ).

In a preferred embodiment of the arithmetic decoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes an extension of the base lookup table in the first direction) and the interval magnitude index (e.g., obtained using a quantization operation Qr2(.), based on the interval magnitude information or the overall interval magnitude information (R)) determines which element of the base lookup table is used to obtain the interval magnitude information.

In a preferred embodiment, the arithmetic decoder is configured to obtain an interval size value R _XPS (e.g. R _LPS ) according to:

_R i/μ )

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., total interval size information (R)); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

An embodiment according to the present invention is an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g. binary values), wherein the arithmetic decoder is configured to derive an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously decoded symbol values (e.g. sequences of binary values 0 and 1) (e.g. having different adaptation time constants), which are associated with a given context mode, indicated for example by an index k; The arithmetic decoder is configured to determine an interval size value (R _LPS ) based on a (current) probability value derived from one or more state variable values and based on a (current) coding interval size (R), using a probability table (ProbTabLPS) (the dimension of which is smaller than the number of possible probability indices i in terms of probability indices), wherein the probability table describes interval sizes (interval size values) for a set of a plurality of probability values (e.g. for probability indices between 0 and μ-1) and for (a) given (reference) coding interval size, and the arithmetic decoder scales an element of the probability table (Prob_TabLPS) (e.g. an element selected depending on the current probability value) to determine the interval size if the current probability value is not within the set of the plurality of probability values (e.g. if the probability index associated with the current probability value is greater than or equal to μ) and/or if the current coding interval size (R) is different from the given (reference) coding interval size. An arithmetic decoder is generated, wherein the arithmetic decoder is configured to obtain a value [R _LPS ); and the arithmetic decoder is configured to perform an arithmetic encoding of one or more symbols using the interval size value (R _LPS ).

In a preferred embodiment, the arithmetic decoder is configured to obtain an interval size value using a first scaling of a selected element (probTabLPS[i%μ]) of the probability table depending on the (current) coding interval size R, and a second scaling of a result of the first scaling depending on whether an element associated with a current probability value (indicated by index i) is included in the set of probability values (e.g. depending on whether the current probability falls within a range of a plurality of probability values covered by the probability table).

In a preferred embodiment of the arithmetic decoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or wherein the coding interval size (R) determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is configured to obtain an interval size value R _XPS (e.g. R _LPS ) according to:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (e.g., the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment, the arithmetic decoder is configured to obtain an interval size value by using a first scaling of a selected element (probTabLPS[i%μ]) of the probability table, depending on whether an element associated with a current probability value (specified by index i) is included in the probability values (e.g. depending on whether the current probability value is within the range of probability values covered by the probability table), and using a second scaling of the result of the first scaling depending on the coding interval size (R).

In a preferred embodiment of the arithmetic decoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ or a ^{-b i/μ} ) and/or wherein the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is configured to obtain an interval size value R _XPS (e.g. R _LPS ) according to:

Here, i is the table index associated with the probability information; j is the table index associated with the (current) interval size information; % is the division remainder operation;

/ is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (e.g., the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

From now on, some additional embodiments related to arithmetic encoding will be described.

An embodiment according to the present invention is an arithmetic encoder for encoding a plurality of symbols having symbol values (e.g. binary values), wherein the arithmetic encoder is configured to determine one state variable value (s _k ) representing statistics of a plurality of previously encoded symbol values, and wherein the arithmetic encoder is configured to determine a combined state variable value, or a scaled version and/or a rounded version of the combined state variable value ( s ^k * a ^k ), the subinterval width value for arithmetic encoding of the symbol value to be encoded ( ), one state variable value (s _k ) or a scaled version and/or rounded version of one state variable value ( s ^k * a ^k ; ), the combined state variable values, or a scaled version and/or rounded version of the combined state variable values ( s ^k * a ^k ; ) is a one-dimensional lookup table containing probability values for different value intervals in the value domain. ) entry is used to map to a probability value, and the coding interval size information (e.g., R) describing the size of the coding interval of the arithmetic encoding prior to the arithmetic encoding of the symbol value to be encoded is used as the quantization level ( ) and is configured to determine a product between the probability value and the quantization level (e.g., by a lookup operation of precomputed products, or by a multiplication), and the arithmetic encoder generates an arithmetic encoder configured to perform a state variable value update depending on the symbol value to be encoded.

This embodiment is based on the discovery that a very simple, one-dimensional lookup table can be used to determine subinterval width values based on the associated state variable values. The coding interval size is taken into account by quantizing the coding interval size information and by determining the product between the probability value and the quantization value (or quantization level). Thus, reliable results are obtained with reasonable effort.

In a preferred embodiment, the arithmetic encoder is configured to derive a combined state variable value (which may be, for example, a weighted sum of the state variable values), as a single state variable value (s _k ), based on a plurality of state variable values (s i k ) (e.g. a sequence of binary values 0 and 1 ⁾ representing statistics of a plurality of previously encoded symbol values (e.g. a sequence of binary values 0 and 1 ) with different _adaptation time constants (e.g. the statistics with different adaptation time constants, if there are multiple state variable values).

It was found that using combined state variable values as a single state variable value leads to particularly good results. Considering different adaptation time constants allows considering both short-term and long-term statistics, which makes the subinterval width values particularly reliable.

In a preferred embodiment, the arithmetic encoder is configured to determine a weighted sum of the state variable values to obtain the combined state variable values.

This computation of the combined state variable values allows taking into account the different influences of short-term and long-term statistics on the combined state variable values while keeping the computational effort reasonably small.

In a preferred embodiment, the arithmetic encoder comprises a state variable value (s _k ) to obtain the combined state variable value (s k ). ) and associated weight values ( ) is the rounded value obtained by rounding the product of ) is configured to determine the sum of the two.

Applying rounding operations before summing reduces computational effort and also eliminates the effect of very small product of state variable values and associated weight values. Therefore, reliability is increased.

In a preferred embodiment, the arithmetic encoder is configured to determine the combined state variable values s _k according to:

Here, s ^k ₂ is the state variable value, N is the number of state variable values considered, . is a floor operator, and d ^k _i is a weight associated with the state variable values (e.g., a weighting factor controlling the influence of an individual state variable value on the combined state variable value) (wherein d ^k _i is a potential, preferably integer-valued, of 2, and the ratio between two different d ^k _i is preferably an integer-valued potential of 2) (wherein the ratio between two different d ^k _i is preferably greater than or equal to 8).

It has been found that deriving the values of the coupled state variables in this way is particularly advantageous. See also the aforementioned description of the corresponding concept for determining the values of the coupled state variables.

In a preferred embodiment, the arithmetic encoder performs a state variable value update when a plurality of state variable values It is configured to update as follows:

Here, z is a predetermined (constant) offset value; is one or more weights; is one or more weights, and A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size (e.g. go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical formula described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero), here , , , and are predetermined parameters (examples are stated above).

It has been found that updating the combined state variable values in this way is particularly advantageous. Also see the above discussion of this concept for updating state variables.

In a preferred embodiment, the arithmetic encoder is configured to derive by table lookup operation or by calculation.

In connection with this concept, see the explanation given above.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here A is a lookup table (e.g. containing integer values) and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

Regarding the advantages of this concept for updating the values of one or more state variables, see the description given above.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

Regarding the advantages of this concept for updating the values of one or more state variables, see the description given above.

In a preferred embodiment, the arithmetic encoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

Regarding the advantages of this concept for updating the values of one or more state variables, see the description given above.

In a preferred embodiment, the arithmetic encoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

The logical right transition of coding interval size information is highly computationally efficient.

In a preferred embodiment, the arithmetic encoder comprises: coding interval size information Quantizing it is configured to perform by, and hereby , and is a parameter.

Regarding the advantages of this quantization of the coding interval size information, see the explanation given above.

In a preferred embodiment of the arithmetic encoder, an entry of the one-dimensional lookup table contains: a value of said one state variable, or a scaled version and/or a rounded version of said one state variable value; s ^k * a ^k ) monotonically decreases as the value of increases.

Regarding the advantages of this structure of a one-dimensional lookup table, see the explanation given above.

In a preferred embodiment of the arithmetic encoder, the one state variable value, or a scaled version and/or a rounded version of the one state variable value ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

Regarding the advantages of this concept, see the explanation given above.

In a preferred embodiment of the arithmetic encoder, an entry of the one-dimensional lookup table contains: a value of said one state variable, or a scaled version and/or a rounded version of said one state variable value; s ^k * a ^k ) monotonically decreases with an increasing rate.

Regarding the advantages of this concept, see the explanation given above.

Hereinafter, the concept for arithmetic decoding will be described, corresponding to the above-described concept for arithmetic encoding. Accordingly, the same explanation also applies, and the same details described above can be optionally used. However, it should be noted that the arithmetic encoder corresponds to the arithmetic decoder. Furthermore, the previously encoded symbol value typically corresponds to the previously decoded symbol value, and the symbol value to be encoded may typically correspond to the previously decoded symbol value (or the symbol value to be decoded). However, with respect to the correspondence of features, it is also referred to compare the corresponding claims defining the related (or corresponding) concept.

An embodiment according to the present invention comprises an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic decoder is configured to derive interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values ( _si ^k ) representing statistics (e.g., an estimate of the probability that one or more symbols to be decoded include a particular symbol value) of a plurality of previously decoded symbol values (e.g., a sequence of binary values 0 and 1) with different adaptation time constants, wherein the arithmetic decoder obtains interval size information (e.g., p _k or R*p _k ) describing an interval size for arithmetic decoding of one or more symbols to be decoded by using a first state variable value (sk1), or a scaled value of the first state variable value. Version and/or rounded version ( sk1* ak1 ), using a lookup table (LUT1), and mapping the second state variable value (s ^k ₂ ), or a scaled version and/or rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is configured to map using a lookup table (LUT1).

In a preferred embodiment, the arithmetic decoder comprises: a scaled version and/or a rounded version of the first state variable value, or sk1* ak1 ) is configured to map the first probability value (p _k ¹ ) using the lookup table, and the arithmetic decoder is configured to map the second state variable value, or a scaled version and/or a rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is configured to map the first probability value (p _k ^{2 ) to a second probability value (p k 2} ) using the lookup table, and the arithmetic decoder is configured to obtain a combined probability value (pk) using the first probability value and the second probability value (e.g., using weighted summation or weighted averaging).

In a preferred embodiment, the arithmetic decoder is configured to change the state variable value in a first direction (e.g., to become a larger positive number) if the decoded symbol has a first value (e.g., "1"), and to change the state variable value in a second direction (e.g., to become a larger negative number) if the decoded symbol has a second value different from the first value (e.g., "0") (e.g., so that the state variable value can have both positive and negative values), and the arithmetic decoder is configured to determine which lookup-table entry to evaluate depends on the ^absolute value of the individual state variable value ( _e.g. , _depends on a scaled and rounded version of the absolute value of the state ^variable _value ⁾ (e.g., depends on a scaled and rounded version of the absolute value of the state variable value).

In a preferred embodiment, the arithmetic decoder, if the first state variable value has a first sign (e.g., a positive sign), sets the first probability value (p _k ¹ ) to a value provided by the lookup table (e.g., ), and the arithmetic decoder is configured to set the first probability value (p _k ¹ ) to a value obtained by subtracting a value provided by the lookup table from a predetermined value (e.g., 1), if the first state variable value has a second sign (e.g., a negative sign), (e.g., It is configured to set (as shown).

In a preferred embodiment, the arithmetic decoder is configured to determine two or more probability values p ^k _i according to

Here, LUT1 is a lookup table containing probability values; . is the floor operator; s ^k _i is the i-th state variable value; a ^k _i is a weight associated with the i-th state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

In a preferred embodiment, the arithmetic decoder is configured to determine two or more probability values p ^k _i according to

Here, LUT1 is a lookup table containing probability values; . is the floor operator; s ^k _i is the i-th state variable value; a ^k _i is a weight associated with the i-th state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

In a preferred embodiment, the arithmetic decoder is configured to obtain a combined probability value p ^k depending on a plurality of probability values p ^k _i according to:

Here, N is the number of probability values considered (and can be equal to the number of state variable values considered); b ^k _i are weights (e.g., weighting factors controlling the influence of individual state variable values on the combined probability value) (wherein b ^k _i are preferably integer-valued potencies of 2, and the ratio between two different b ^k _i is preferably an integer-valued potency of 2).

In a preferred embodiment, the arithmetic decoder outputs a value of the first state variable, or a scaled version and/or a rounded version of the value of the first state variable ( sk1* ak1 ) is configured to map a first subinterval width value (R*p k 1 ) using a two-dimensional lookup table, the entry of which is addressed depending on the first state variable value (e.g., to determine the first lookup table entry coordinate) and depending on coding interval size information (e.g., R) describing the size of a coding interval of the arithmetic decoding prior to decoding of the symbol (e.g., to determine the ^second lookup _table entry coordinate),

Here, the arithmetic decoder outputs a scaled version and/or rounded version of the second state variable value, or a scaled version and/or rounded version of the second state variable value ( sk1* ak1 ) is configured to map a second subinterval width value (R*p k 2 ) using a two-dimensional lookup table, the entry of which depends on the second state variable value (e.g., to determine the first lookup table entry coordinate) and is addressed depending on coding interval size information (e.g., R) describing the size of a coding interval of the arithmetic decoding prior to decoding of the symbol (e.g., to determine the second ^lookup _table entry coordinate).

In a preferred embodiment of the arithmetic decoder, the two-dimensional lookup table comprises: a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ; ) comprising a first 1-dimensional vector entry (forming a one-dimensional lookup table) containing probability values for different value intervals of the value domain, and a second 1-dimensional vector ( comprising a quantization level for the coding interval size information) ) can be expressed as a dyadic product between entries.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a base lookup table (Base TabLPS), a first group (or block; e.g., "upper half") of the elements of the two-dimensional lookup-table are identical to the elements of the base lookup-table or are rounded versions of the elements of the base lookup-table, and a second group (or block; e.g., "lower half") of the elements of the two-dimensional lookup-table are scaled versions and rounded versions of the elements of the base lookup-table.

In a preferred embodiment of the arithmetic decoder, the second group of elements of the two-dimensional lookup-table are right-shifted versions of the elements of the base lookup table.

In a preferred embodiment of the arithmetic decoder, the probability indices (Qp ₂ (p _LPS ) or i)) determine whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated, and a first range (e.g. between 0 and μ-1) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS ) is associated with elements of the first group of elements, and a second range (e.g. greater than or equal to μ) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS , using, for example, a quantization function Qp2(.) ) is associated with elements of the second group of elements.

In a preferred embodiment of the arithmetic decoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes an extension of the base lookup table in the first direction) and an interval magnitude index (e.g., based on the interval magnitude information (R), which can be obtained, for example, using a quantization operation Qr2(.); for example, j) determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table.

In a preferred embodiment, the arithmetic decoder is configured to obtain elements of a two-dimensional lookup table (RangTabLPS) according to:

RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j), i/μ )

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., describing the current coding interval size); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a probability table (probTabLPS), the probability table describing interval sizes for a set of a plurality of probability values (e.g. represented by an index i) and for a given (reference) coding interval size, and the elements of the two-dimensional lookup-table for probability values not included in the set of the plurality of probability values and/or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table are obtained using a first scaling (multiplication) of a selected element (probTabLPS[i%μ]) of the probability table depending on the coding interval size R, and a second scaling of the result of the first scaling depending on whether the element associated with the current probability value (indicated by the index i) is included in the set of probability values (e.g. depending on whether the current probability falls within the range of probability values covered by the probability table).

In a preferred embodiment of the arithmetic decoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or wherein the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (or the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment of the arithmetic decoder, an element of the two-dimensional lookup-table is obtained by using a first scaling of a selected element of the probability table (probTabLPS[i%μ]) depending on whether the element associated with the current probability value (indicated by index i) is included in the set of probability values (e.g. depending on whether the current probability value is within the range of probability values covered by the probability table), and using a second scaling of the result of the first scaling depending on the coding interval size (R).

In a preferred embodiment of the arithmetic decoder, the division remainder of the division between a probability index (e.g. i; e.g. representing the current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes the extension of the probability table) i%μ ) determines which element of said probability table is scaled in said first scaling; and/or an integer division result () of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size; Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment, the arithmetic decoder outputs a scaled version and/or rounded version of the first state variable value and the second state variable value, or the first state variable value and the second state variable value ( s ^k * a ^k ), the first and second subinterval width values (R*p ^k ) are obtained from the first and second state variable values (s _k ) or the scaled versions and/or rounded versions of the first and second state variable values ( s ^k ₂ * a ^k ₂ ), the first state variable value and the second state variable value, or the scaled version and/or rounded version of the first state variable value and the second state variable value ( s ^k * a ^k ) is mapped to first and second probability values using a one-dimensional lookup table (LUT4) entry including probability values for different value intervals of the value domain for the symbol, and quantizes coding interval size information (R) describing a size of a coding interval of the arithmetic encoding prior to encoding of a symbol into a quantization level, and in one aspect, determines a product of the first and second probability values and the quantization level (by looking up or multiplying pre-computed products), and obtains a combined subinterval width value by using the first subinterval width value and the second subinterval width value (for example, by using a weighted summation or a weighted average), thereby calculating the combined subinterval width value.

In a preferred embodiment, the arithmetic decoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

In a preferred embodiment, the arithmetic decoder comprises: coding interval size information Quantizing it is configured to perform by, and hereby , and is a parameter.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table comprises a scaled version and/or a rounded version of the first state variable value and the second state variable value, or a scaled version and/or a rounded version of the first state variable value and the second state variable value. s ^k * a ^k ) monotonically decreases as the value of increases.

In a preferred embodiment of the arithmetic decoder, the first state variable value and the second state variable value, or scaled versions and/or rounded versions of the first state variable value and the second state variable value ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table comprises: a value of the first and second state variables, or a scaled version and/or a rounded version of the first and second state variables; s ^k * a ^k ) monotonically decreases with an increasing rate.

An embodiment according to the present invention comprises an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g. binary values), wherein the arithmetic decoder is configured to derive interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values (s i k ) representing statistics (e.g. an estimate of the probability that one or more symbols to be decoded will include a particular symbol value) of a plurality of previously decoded symbol values (e.g. a sequence of binary values 0 _and 1) with different adaptation time constants (these are associated with a given context mode, indicated for example by an index k ), wherein the arithmetic decoder is configured to derive a combined probability variable value (s ^k ) (which may for example be a weighted sum of the state variable values) based on the plurality of (individual) state variable values (s i _k ), wherein the arithmetic decoder is configured to derive an associated probability variable value ( _s ^k ) (which may for example be a weighted sum of the state variable values) of one or more to be decoded symbol values. To obtain the interval size information (e.g., p _k or R*p _k ) describing the interval size for arithmetic decoding of the symbol, the combined state variable value (sk), or a scaled version and/or a rounded version of the combined state variable value ( s ^k ₂ * a ^k ₂ ) is configured to map using a lookup table (LUT1).

In a preferred embodiment, the arithmetic decoder is configured to determine a weighted sum of the state variable values to obtain the combined state variable values.

In a preferred embodiment, the arithmetic decoder comprises a state variable value (s _k ) to obtain the combined state variable value (s k ). ) and associated weight values ( ) is the rounded value obtained by rounding the product of ) is configured to determine the sum of the two.

In a preferred embodiment, the arithmetic decoder is configured to determine the combined state variable values s _k according to:

Here, s ^k ₂ is the state variable value, N is the number of state variable values considered, . is a floor operator, and d ^k _i is a weight associated with the state variable values (e.g., a weighting factor controlling the influence of an individual state variable value on the combined state variable value) (wherein d ^k _i is a potential, preferably integer-valued, of 2, and the ratio between two different d ^k _i is preferably an integer-valued potential of 2) (wherein the ratio between two different d ^k _i is preferably greater than or equal to 8).

In a preferred embodiment, the arithmetic decoder is configured to change the state variable value in a first direction (e.g., to become a larger positive number) if the decoded symbol has a first value (e.g., "1"), and to change the state variable value in a second direction (e.g., to become a larger negative number) if the decoded symbol has a second value different from the first value (e.g., "0") (e.g., so that the state variable value can have both positive and negative values), and the arithmetic decoder is configured to determine which entry of the lookup-table to be evaluated depends on the absolute value of the combined state variable value (e.g., depends on a scaled and rounded version of the absolute value of the combined state variable value) (e.g., depends on a scaled and rounded version of the absolute value of the combined state variable value) depending on the absolute value of the combined state variable value (s _k i if s _k ⁱ >0, otherwise _-s k i).

In a preferred embodiment, the arithmetic decoder, if the associated state variable value has a first sign (e.g., a positive sign), sets the probability value (p ^k ) to a value provided by the lookup table (e.g., ), and the arithmetic decoder is configured to set the probability value (p ^k ) to a value obtained by subtracting a value provided by the lookup table from a predetermined value (e.g., 1), if the combined state variable value has a second sign (e.g., a negative sign), (e.g., It is configured to set (as shown).

In a preferred embodiment, the arithmetic decoder is configured to determine the combined probability value p _k according to:

Here, LUT2 is a lookup table containing probability values; . is a floor operator; s ^k is a combined state variable value; a ^k is a weight associated with the combined state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

In a preferred embodiment, the arithmetic decoder is configured to determine the combined probability value p _k according to:

Here, LUT2 is a lookup table containing probability values; . is a floor operator; s ^k is a combined state variable value; a ^k is a weight associated with the combined state variable value (e.g., a weight that adapts the number range of the i-th state variable value to the number of entries in the lookup table).

In a preferred embodiment, the arithmetic decoder comprises: a scaled version and/or a rounded version of the combined state variable values, or s ^k * a ^k ) is configured to map subinterval width values (R*p k ) using a two-dimensional lookup table, the entries of which depend on the combined state variable values (e.g., to determine the first lookup table entry coordinates) and on coding interval size information (e.g., R) describing the size of a coding interval of the arithmetic decoding prior to decoding of the symbol (e.g., to determine the second lookup ^table entry coordinates).

In a preferred embodiment of the arithmetic decoder, the two-dimensional lookup table comprises: the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values; s ^k * a ^k ; ) contains probability values for different value intervals in the value domain, the first 1-dimensional vector entry ( ; forming a one-dimensional lookup table), and a second one-dimensional vector ( comprising a quantization level for the coding interval size information ) can be expressed as a dyadic product between entries.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a base lookup table (Base TabLPS), a first group (or block; e.g., "upper half") of the elements of the two-dimensional lookup-table are identical to the elements of the base lookup-table or are rounded versions of the elements of the base lookup-table, and a second group (or block; e.g., "lower half") of the elements of the two-dimensional lookup-table are scaled versions and rounded versions of the elements of the base lookup-table.

In a preferred embodiment of the arithmetic decoder, the second group of elements of the two-dimensional lookup-table are right-shifted versions of the elements of the base lookup table.

In a preferred embodiment of the arithmetic decoder, the probability indices (Qp ₂ (p _LPS ) or i)) determine whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated, and a first range (e.g. between 0 and μ-1) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS ) is associated with elements of the first group of elements, and a second range (e.g. greater than or equal to μ) of the probability indices (which are obtained, for example, by quantizing the probability values, e.g. p _LPS , using, for example, a quantization function Qp2(.) ) is associated with elements of the second group of elements.

In a preferred embodiment of the arithmetic decoder, the division remainder (i%μ) of the division between the probability index (i) and the first magnitude value (e.g. μ; where, for example, the magnitude value describes an extension of the base lookup table in the first direction) and an interval magnitude index (e.g., based on the interval magnitude information (R), which can be obtained, for example, using a quantization operation Qr2(.); for example, j) determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table.

In a preferred embodiment, the arithmetic decoder is configured to obtain elements of a two-dimensional lookup table (RangTabLPS) according to:

RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j), i/μ )

Here, BaseTabLPS is a base lookup table of dimension μ x λ; i is a table index associated with probability information; j is a table index associated with interval size information (e.g., describing the current coding interval size); % is a division remainder operation; / is a division operation; and Scal(x, y) is a scaling function (e.g., Scal(x, y) = x*a ^-by As defined, . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table (RangTabLPS) are defined based on a probability table (probTabLPS), the probability table describing interval sizes for a set of a plurality of probability values (e.g. represented by an index i) and for a given (reference) coding interval size, and the elements of the two-dimensional lookup-table for probability values not included in the set of the plurality of probability values and/or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling.

In a preferred embodiment of the arithmetic decoder, the elements of the two-dimensional lookup-table are obtained using a first scaling (multiplication) of a selected element (probTabLPS[i%μ]) of the probability table depending on the coding interval size R, and a second scaling of the result of the first scaling depending on whether the element associated with the current probability value (indicated by the index i) is included in the set of probability values (e.g. depending on whether the current probability falls within the range of probability values covered by the probability table).

In a preferred embodiment of the arithmetic decoder, a division remainder (i%μ) of a division between a probability index (e.g. i; e.g. representing a current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes an extension of a probability table) determines which elements of said probability table are scaled in said first scaling; and/or an integer division result (i%μ) of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or wherein the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is configured to obtain elements of a two-dimensional lookup-table according to:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation; probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size (or the current coding interval size); Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment of the arithmetic decoder, an element of the two-dimensional lookup-table is obtained by using a first scaling of a selected element of the probability table (probTabLPS[i%μ]) depending on whether the element associated with the current probability value (indicated by index i) is included in the set of probability values (e.g. depending on whether the current probability value is within the range of probability values covered by the probability table), and using a second scaling of the result of the first scaling depending on the coding interval size (R).

In a preferred embodiment of the arithmetic decoder, the division remainder of the division between a probability index (e.g. i; e.g. representing the current probability value) and a first magnitude value (e.g. μ; where, e.g. the magnitude value describes the extension of the probability table) i%μ ) determines which element of said probability table is scaled in said first scaling; and/or an integer division result () of the division between said probability index (i) and said first magnitude value ( i/μ ) is the scaling factor (2-) used in the second scaling. ^i/μ ) and/or the coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling.

In a preferred embodiment, the arithmetic decoder is an element of a two-dimensional lookup table. It is configured to obtain as follows:

Here, i is a table index associated with probability information; j is a table index associated with interval size information; % is a division remainder operation; / is a division operation (e.g., giving an integer result); probTabLPS[] is a probability table; μ is the number of elements in the probability table (where the range of values of i is typically larger than μ); R is an interval size; Qr ₂ (R) is a scaling factor that depends on R; Scal(x, y) is a scaling function (e.g., Scal(x, y)= x*a ^-by is defined as, and here . is a floor operation, a is preferably a constant greater than or equal to 2, b is preferably a constant greater than or equal to 1, the scaling function is preferably implemented using a right-shift bitwise transition operation, and y determines whether a right-shift of x is performed and how many bits are shifted.

In a preferred embodiment, the arithmetic decoder comprises: a scaled version and/or a rounded version of the combined state variable values, or s ^k * a ^k ), the subinterval width value (R*p ^k ), the combined state variable value (s _k ) or the scaled version and/or rounded version of the combined state variable value ( s ^k * a ^k ; ), the combined state variable values, or a scaled version and/or rounded version of the combined state variable values ( s ^k * a ^k ; ) is configured to map a combined probability value using a one-dimensional lookup table (LUT4) entry including probability values for different value intervals of the value domain, quantize coding interval size information (e.g., R) describing a size of a coding interval of the arithmetic encoding prior to encoding of a symbol into a quantization level, and calculate a product of the combined probability value and the quantization level (by looking up pre-computed products or by multiplication).

In a preferred embodiment, the arithmetic decoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

In a preferred embodiment, the arithmetic decoder comprises: coding interval size information Quantizing it is configured to perform by, and hereby , and is a parameter.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table contains: the combined state variable value, or a scaled version and/or a rounded version of the combined state variable value ( s ^k * a ^k ) monotonically decreases as the value of increases.

In a preferred embodiment of the arithmetic decoder, the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table contains: the combined state variable value, or a scaled version and/or a rounded version of the combined state variable value ( s ^k * a ^k ) monotonically decreases with an increasing rate.

In a preferred embodiment of the arithmetic decoder, the lookup-table specifies an exponential decay (e.g., decreasing from 0.5) (e.g., within a tolerance of +/-10% or +/-20%).

In a preferred embodiment, the arithmetic decoder has multiple variable state values. It is configured to update as follows:

Here, z is a predetermined (constant) offset value; is one or more weights; is one or more weights, and A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size (e.g. go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical formula described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero), here , , , and are predetermined parameters (examples are stated above).

In a preferred embodiment, the arithmetic decoder is configured to derive by table lookup operation or by calculation.

An embodiment according to the present invention is an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g., binary values), wherein the arithmetic decoder is configured to determine one or more state variable values (s 1 k , s 2 k ) representing statistics (e.g., statistics having different adaptive time constants when multiple state variable values are determined) of a plurality of previously decoded symbol values (e.g., sequences of binary values ₀ and ₁ ⁾ (e.g., estimates of the probability that one or more ^symbols to be decoded have a specific symbol value), and the arithmetic decoder is configured to determine interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded, and one or more state variable values (s i k ) representing statistics (e.g., statistics having different adaptive time constants when multiple state variable values are determined) of a plurality of previously decoded symbol values (e.g., sequences of binary values 0 _and ¹⁾ . ) (which are associated with a given context mode denoted by k for example), and the arithmetic encoder generates an arithmetic decoder configured to update a first state variable value (s ^k ₁ ) depending on the decoded symbol and using a lookup table (A) (for example, after decoding the symbol to be decoded).

In a preferred embodiment, the arithmetic decoder is configured to update the second state variable value (s ^k ₂ ) depending on the decoded symbol and using the lookup table (A) (e.g., after decoding the symbol to be decoded).

In a preferred embodiment, the arithmetic decoder is configured to update the first state variable value and the second state variable value using different adaptation time constants.

In a preferred embodiment, the arithmetic decoder is configured to selectively increment or decrement a previous state variable value by a value determined using the lookup table, depending on whether the decoded symbol has a first value or a second value different from the first value.

In a preferred embodiment, the arithmetic decoder is configured to, if the decoded symbol has a first value, increment a previous state variable value by a relatively larger value if the previous state variable value is negative compared to the case where the previous state variable value is positive, and the arithmetic decoder is configured to, if the decoded symbol has a second value different from the first value (which is obtained, for example, by appropriately selecting a look-up table), decrement the previous state variable value by a relatively larger value if the previous state variable value is positive compared to the case where the previous state variable value is negative.

In a preferred embodiment, the arithmetic decoder, if the decoded symbol has a first value, outputs a predetermined (e.g., fixed) offset value (z) and a previously computed first state variable value ( ), or a scaled version and/or rounded version of the previously computed first state variable value ( ) is configured to determine an index of an entry of the lookup table to be evaluated when updating the first state variable value, depending on the sum of the first and second values, and the arithmetic decoder is configured to, if the decoded symbol has a second value, compute a predetermined (e.g., fixed) offset value (z) and an inverted (multiplied by -1) version of the previously computed first state variable value ( ), or a scaled version and/or a rounded version thereof (an inverted version of the previously computed first state variable value). ) is configured to determine the index of an entry of the lookup table to be evaluated when updating the value of the first state variable.

In a preferred embodiment, the arithmetic decoder, if the decoded symbol has a second value, calculates a predetermined (e.g., fixed) offset value (z) and a previously computed second state variable value ( ), or a scaled version and/or rounded version of the previously computed second state variable value ( ) is configured to determine an index of an entry of the lookup table to be evaluated when updating the second state variable value, depending on the sum of the values of the lookup table, and the arithmetic decoder is configured to determine, if the symbol to be encoded has a second value, an offset value (z) that is predetermined (e.g., fixed) and an inverted (multiplied by -1) version of the previously computed second state variable value ( ), or a scaled version and/or rounded version thereof (an inverted version of the previously computed second state variable value). ) is configured to determine the index of an entry of the lookup table to be evaluated when updating the value of the second state variable.

In a preferred embodiment, the arithmetic decoder is configured to apply a first scaling value (m k 1 ) to scale a previously computed first state variable value (s ^k ₁ ) when determining an index of an entry of the lookup table to be evaluated when updating the first state variable value, and the arithmetic decoder is configured to apply a second scaling value (m ^k ₂ ) to scale a previously computed second state variable value (s ^k ₂ ) when determining an index of an ^entry of the lookup table to be evaluated when updating the second state variable value, wherein the first scaling value is different from the second scaling value (and, wherein the first and second scaling values are preferably integer potentials of ₂ , and a ratio between the first scaling value and the second scaling value is preferably integer potentials of 2, and the first scaling value and the second scaling value are different from each other by at least a factor of 8). (preferable).

In a preferred embodiment, the arithmetic decoder is configured to scale the value returned by the evaluation of the lookup table when updating the value of the first state variable using a first scaling value (e.g., n ^k ₁ ).

The arithmetic decoder is configured to scale a value returned by evaluating the lookup table when updating the second state variable value, using a second scaling value (e.g., n ^k ₂ ), wherein the first scaling value is different from the second scaling value.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder is configured to @determine one or more updated state variable values according to:

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment of the arithmetic decoder, the entries of A monotonically decrease as the lookup table index increases.

In a preferred embodiment of the arithmetic decoder, A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size (e.g. go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical expression described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero). Here , , , and are predetermined parameters (examples are stated above).

In a preferred embodiment of the arithmetic decoder, the last entry of the lookup table (addressed when the first state variable value reaches a predetermined range of values extending to a maximum allowable value, or when the first state variable value exceeds a predetermined threshold value) is equal to zero.

In a preferred embodiment, the arithmetic decoder is configured to apply a clipping operation to the updated state variable values so as to keep the updated state variable values and the clipped state variable values within a predetermined range of values.

In a preferred embodiment, the arithmetic decoder performs the clipping operation according to

It is configured to apply to the updated state variable values, where Is is the maximum allowable value for Is is the minimum allowable value for .

In a preferred embodiment, the arithmetic decoder is configured to apply different scaling values for different context models (e.g., to cause at least one of the scaling values to vary between two different context models).

In a preferred embodiment, the arithmetic decoder is configured to obtain interval size information as specified in one of the embodiments described above.

An embodiment according to the present invention is an arithmetic decoder for decoding a plurality of symbols having symbol values (e.g. binary values), wherein the arithmetic decoder is configured to determine one state variable value (s _k ) representing statistics of a plurality of previously decoded symbol values, and wherein the arithmetic decoder is configured to determine a combined state variable value, or a scaled version and/or a rounded version of the combined state variable value ( s ^k * a ^k ), the subinterval width value for arithmetic decoding of the symbol value to be decoded ( ), one state variable value (s _k ) or a scaled version and/or rounded version of one state variable value ( s ^k * a ^k ; ), the combined state variable values, or a scaled version and/or rounded version of the combined state variable values ( s ^k * a ^k ; ) is a one-dimensional lookup table containing probability values for different value intervals in the value domain. ) entry is mapped to a combined probability value, and coding interval size information (e.g., R) describing the size of the coding interval of the arithmetic decoding prior to the arithmetic decoding of the symbol value to be decoded is provided at the quantization level ( ) and is configured to determine a product between said probability value and said quantization level (e.g., by a lookup operation of precomputed products, or by a multiplication), and wherein said arithmetic decoder generates an arithmetic decoder configured to perform a state variable value update depending on a symbol value to be decoded (actually decoded).

In a preferred embodiment, the arithmetic decoder is configured to derive a combined state variable value (which may be, for example, a weighted sum of the state variable values) as a single state variable value (s _k ), depending on a plurality of state variable values (s _{i k )} (e.g. a sequence of binary values 0 and 1 ) representing statistics of a plurality of previously decoded symbol values (e.g. a sequence of binary values 0 and 1 ) with different adaptation time ^constants (e.g. the statistics having different adaptation time constants in the case of multiple state variable values).

In a preferred embodiment, the arithmetic decoder is configured to determine a weighted sum of the state variable values to obtain the combined state variable values.

In a preferred embodiment, the arithmetic decoder comprises a state variable value (s _k ) to obtain the combined state variable value (s k ). ) and associated weight values ( ) is the rounded value obtained by rounding the product of ) is configured to determine the sum of the two.

In a preferred embodiment, the arithmetic decoder is configured to determine the combined state variable values s _k according to:

Here, s ^k ₂ is the state variable value, N is the number of state variable values considered, . is a floor operator, and d ^k _i is a weight associated with the state variable values (e.g., a weighting factor controlling the influence of an individual state variable value on the combined state variable value) (wherein d ^k _i is a potential, preferably integer-valued, of 2, and the ratio between two different d ^k _i is preferably an integer-valued potential of 2) (wherein the ratio between two different d ^k _i is preferably greater than or equal to 8).

In a preferred embodiment, the arithmetic decoder performs a state variable value update when a plurality of state variable values It is configured to update as follows:

Here, z is a predetermined (constant) offset value; is one or more weights; is one or more weights, and A is This or updated To avoid going beyond a predetermined range of values, it deviates from it only for one or more extreme values of its argument, either by setting it to zero or by reducing its size (e.g. go Consider that it has a larger value domain; that is, Is is quantized into ; For extreme values of , is modified by A, which is not modified according to the mathematical formula described above, and thus goes out of its value domain; to avoid this, the entries corresponding to these extreme values can be reduced or treated as zero), here , , , and are predetermined parameters (examples are stated above).

In a preferred embodiment, the arithmetic decoder is configured to derive by a table lookup operation or by calculation.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder updates one or more state variable values is configured to determine according to the following,

Here, A is a lookup table (e.g., containing integer values), and z is a predetermined (constant) offset value; here is one or more weights; is one or more weights.

In a preferred embodiment, the arithmetic decoder is configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information.

In a preferred embodiment, the arithmetic decoder comprises: coding interval size information Quantizing it is configured to perform by, wherein, , and is a parameter.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table contains: a value of said one state variable, or a scaled version and/or a rounded version of said one state variable value; s ^k * a ^k ) monotonically decreases as the value of increases.

In a preferred embodiment of the arithmetic decoder, the one state variable value, or a scaled version and/or a rounded version of the one state variable value ( s ^k * a ^k ) for different value intervals in the value domain are sized identically.

In a preferred embodiment of the arithmetic decoder, an entry of the one-dimensional lookup table contains: a value of said one state variable, or a scaled version and/or a rounded version of said one state variable value; s ^k * a ^k ) monotonically decreases with an increasing rate.

An embodiment of the present invention produces a video encoder, wherein the video encoder is configured to encode a plurality of video frames, the video encoder including an arithmetic encoder for providing an encoded binary sequence based on a sequence of binary values representing video content, according to one of the embodiments described above.

It should be noted that the arithmetic encoder described herein is well suited for use within a video encoder. In such a case, the symbols to be encoded and/or previously encoded symbols may be symbols of a video bit stream. For example, the symbols to be encoded and/or previously encoded symbols may represent bits of side information or control information and/or bits of encoded transform coefficients representing video content. In other words, the symbols to be encoded and/or previously encoded symbols may represent any of the information contained in the bit stream to represent video content. However, it should be noted that the state variable values may be determined individually for different "contexts", i.e., for different types of information. For example, only bits associated with a given type of information (e.g., a particular type of side information) may contribute to a given state variable value or a given set of state variable values, which are used to obtain a given combined state variable value. Therefore, interval size information may be derived individually for different contexts, i.e., for encoding symbol values associated with different types of information (e.g., side information).

An embodiment according to the present invention generates a video decoder, wherein the video decoder is configured to decode a plurality of video frames, the video decoder comprising an arithmetic decoder (120; 220) for providing a decoded binary sequence (e.g., based on decoded symbol values), based on an encoded representation (211) of the binary sequence, according to one of the embodiments described above.

The video decoder is based on the same considerations as the video encoder. Accordingly, the above description applies as well, where the encoded symbol or the symbol to be encoded corresponds to the coded symbol.

Furthermore, it should be noted that additional embodiments according to the present invention create individual methods and computer programs.

An embodiment of the present invention is a method for encoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving interval size information (p ^k , R*p ^k ) for arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g. sequences of binary values of 0 and 1) with different adaptation time constants (which are associated with a given context mode, indicated for example by an index k ), the method comprising: obtaining interval size information (e.g. p _k or R*p _k ) describing an interval size for arithmetic encoding of one or more symbols to be encoded, the first state variable value (s ^k ₁ ), or a scaled version and/or a rounded version of the first state variable value ( s ^k ₁ * a ^k ₁ ), using a lookup table (LUT1), and mapping the second state variable value (s ^k ₂ ), or a scaled version and/or rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is generated, which includes a step of mapping using a lookup table (LUT1).

An embodiment according to the present invention is a method for encoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving interval size information (p k , R*p k ) for an arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values (s _i ^{k )} representing statistics of a plurality of previously encoded symbol values (e.g. sequences of binary values 0 and 1) with different adaptation time constants (which are associated with a given context mode, indicated for example by an index ^k ), the method comprising the step of deriving a combined state variable value ( _s ^k ) (which may for example be a weighted sum of the state variable values), the method comprising obtaining interval size information (e.g. p _k or R*p _{k )} describing an interval size for the arithmetic encoding of one or more symbols to be encoded, based on the plurality of (individual) state variable values (s i _k ). or a scaled version and/or rounded version of the combined state variable values ( s ^k ₂ * a ^k ₂ ) is generated, comprising a step of mapping using a lookup table.

Embodiments according to the present invention are methods for encoding a plurality of symbols having symbol values (e.g., binary values), the method comprising the step of determining one or more state variable values (s 1 k , s ₂ ^k ) representing statistics (e.g., statistics having different adaptation time constants, if there are multiple state variable values) of a plurality of previously encoded symbol values (e.g., sequences of binary values 0 and 1), the method comprising the step of deriving interval size information ( _p ^k , R*p ^{k )} for arithmetic encoding of the one or more symbol values to be encoded, based on one or more state variable values (s _i ^k ) representing statistics (e.g., statistics having different adaptation time constants, if there are multiple state variable values) of the plurality of previously encoded symbol values (e.g., sequences of binary values 0 and 1), the method comprising the step of deriving a first state variable value (s ^k ₁ ) depending on the symbol to be encoded. And generate an encoding method, which includes a step of updating using a lookup table (A) (e.g., after encoding a symbol to be encoded).

An embodiment of the present invention is a method for decoding a plurality of symbols having symbol values (e.g., binary values), the method comprising the step of deriving interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values (s i k ) (which are associated with a given context model, indicated for example by an _index k ) representing statistics (e.g., an estimate of the probability that one or more symbols to be decoded will include a particular symbol value) of a plurality of previously decoded symbol values (e.g., a sequence of binary values 0 and ¹ ) with different adaptation time constants, the method comprising: obtaining interval size information (e.g., p _k or R*p _k ) describing an interval size for arithmetic decoding of one or more symbols to be decoded, the method comprising: deriving a first state variable value (sk1 ), or a scaled version and/or a rounded version of the first state variable value ( sk1* ak1 ), using a lookup table (LUT1), and mapping the second state variable value (s ^k ₂ ), or a scaled version and/or rounded version of the second state variable value ( s ^k ₂ * a ^k ₂ ) is generated, which includes a step of mapping using a lookup table (LUT1).

An embodiment according to the present invention is a method for decoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values (s _i ^k ) representing statistics (e.g. an estimate of the probability that one or more symbols to be decoded will contain a particular symbol value) of a plurality of previously decoded symbol values (e.g. a sequence of binary values 0 and 1) with different adaptation time constants, the method comprising the step of deriving a combined probability variable value (s _k ) (which may be a weighted sum of the state variable values, for example) based on the plurality of (individual) state variable values (s _i ^k ), the method comprising the step of deriving an interval size describing an interval size for arithmetic decoding of one or more symbols to be decoded. To obtain the size information (e.g., p _k or R*p _k ), the combined state variable values (sk), or scaled versions and/or rounded versions of the combined state variable values ( s ^k ₂ * a ^k ₂ ) is generated, which includes a step of mapping using a lookup table (LUT1).

An embodiment according to the present invention is a method for decoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving interval size information (p ^k , R*p ^k ) for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values (s _i ^k ) representing statistics (e.g. an estimate of the probability that one or more symbols to be decoded will contain a particular symbol value) of a plurality of previously decoded symbol values (e.g. a sequence of binary values 0 and 1) with different adaptation time constants, the method comprising the step of deriving a combined probability variable value (s _k ) (which may be a weighted sum of the state variable values, for example) based on the plurality of (individual) state variable values (s _i ^k ), the method comprising the step of deriving an interval size describing an interval size for arithmetic decoding of one or more symbols to be decoded. To obtain the size information (e.g., p _k or R*p _k ), the combined state variable values (sk), or scaled versions and/or rounded versions of the combined state variable values ( s ^k ₂ * a ^k ₂ ) is generated, which includes a step of mapping using a lookup table (LUT1).

Embodiments according to the present invention generate methods performed by an encoder and a decoder according to one of the embodiments described above.

Embodiments according to the present invention create a computer program for performing a method according to one of the embodiments described above when the computer program is executed on a computer.

An embodiment of the present invention is a method for encoding a plurality of symbols having symbol values (e.g., binary values), the method comprising the step of deriving an interval size value (R _LPS ) for an arithmetic encoding of one or more symbol values to be encoded based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g., a sequence of binary values of 0 and 1), the method comprising the step of determining the interval size value (R _LPS ) using a base lookup table (Base TabLPS), the method comprising: if a probability index (i) (e.g., equal to i=Qp(p _LPS )) obtained based on the one or more state variable values is within a first range (e.g., less than μ), then the determined interval size value is equal to an element of the base lookup table or is a rounded version of an element of the base lookup table, and if the probability index is within a second range (e.g., greater than or equal to μ), then the determined The method comprises a step of determining an interval size value (R _LPS ) such that the interval size value is obtained by using scaling and rounding of elements of the base lookup table, and produces an encoding method comprising a step of performing an arithmetic encoding of one or more symbols using the interval size value (R _LPS ).

An embodiment according to the present invention is a method for encoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving an interval size value (R _LPS ) for an arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values (e.g. sequences of binary values 0 and 1) (e.g. having different adaptation time constants), which are associated with a given context mode, indicated for example by an index k; The method comprises the step of determining an interval size value (R _LPS ) based on a (current) probability value derived from one or more state variable values and based on a (current) coding interval size (R), using a probability table (ProbTabLPS) (whose dimension is smaller than the number of possible probability indices i in terms of probability indices), wherein the probability table describes interval sizes (interval size values) for a set of a plurality of probability values (e.g. for probability indices between 0 and μ-1) and for (a) given (reference) coding interval size, and the method comprises the step of scaling an element of the probability table (Prob_TabLPS) (e.g. an element selected depending on the current probability value) to obtain the interval size value [R LPS ) if the current probability value is not in the set of the plurality of probability values (e.g. if the probability index associated with the current probability value is greater than or equal to μ) and/or if the current coding interval size (R) is different from the given ( _reference ) coding interval size; The method produces an encoding method comprising the step of performing an arithmetic encoding of one or more symbols using interval size values (R _LPS ).

An embodiment of the present invention is a method for decoding a plurality of symbols having symbol values (e.g., binary values), the method comprising the step of deriving an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously decoded symbol values (e.g., a sequence of binary values of 0 and 1), the method comprising the step of determining the interval size value (R _LPS ) using a base lookup table (Base TabLPS), the method comprising: if a probability index (i) (e.g., equal to i=Qp(p _LPS )) obtained based on the one or more state variable values is within a first range (e.g., less than μ), then the determined interval size value is equal to an element of the base lookup table or is a rounded version of an element of the base lookup table, and if the probability index is within a second range (e.g., less than μ), The method comprises a step of determining an interval size value (R _LPS ) such that the determined interval size value is obtained by using scaling and rounding of elements of the base lookup table, wherein the method produces a decoding method including a step of performing arithmetic decoding of one or more symbols using the interval size value (R _LPS ).

An embodiment according to the present invention is a method for decoding a plurality of symbols having symbol values (e.g. binary values), the method comprising the step of deriving an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously decoded symbol values (e.g. sequences of binary values 0 and 1) (e.g. having different adaptation time constants), which are associated with a given context mode, indicated for example by an index k; The method comprises the step of determining an interval size value (R _LPS ) based on a (current) probability value derived from one or more state variable values and based on a (current) coding interval size (R), using a probability table (ProbTabLPS) (whose dimension is smaller than the number of possible probability indices i in terms of probability indices), wherein the probability table describes interval sizes (interval size values) for a set of a plurality of probability values (e.g. for probability indices between 0 and μ-1) and for (a) given (reference) coding interval size, and the method comprises the step of scaling an element of the probability table (Prob_TabLPS) (e.g. an element selected depending on the current probability value) to obtain the interval size value [R LPS ) if the current probability value is not in the set of the plurality of probability values (e.g. if the probability index associated with the current probability value is greater than or equal to μ) and/or if the current coding interval size (R) is different from the given ( _reference ) coding interval size; The method produces a decoding method comprising the step of performing an arithmetic encoding of one or more symbols using interval size values (R _LPS ).

Embodiments according to the present invention create a computer program for performing a method according to one of the embodiments described above when the computer program is executed on a computer.

The methods mentioned above are based on the same considerations as the devices described above. However, it should be noted that these methods may optionally be supplemented by any of the features, functionality and details also described with respect to the devices herein. These methods may optionally be supplemented by the features, functionality and details, both individually and in combination. The same holds true for the computer program.

Embodiments according to the present invention will now be described with reference to the attached drawings:
FIG. 1 illustrates a schematic block diagram of an apparatus for predictively coding pictures in a data stream according to one embodiment of the present invention;
FIG. 2 illustrates a schematic block diagram of a decoder according to one embodiment of the present invention;
Figure 3 shows a schematic representation of the relationship between the reconstructed signal and the combination of the prediction residual and the prediction signal;
FIG. 4 illustrates a schematic block diagram of an arithmetic encoder according to one embodiment of the present invention;
FIG. 5 illustrates a schematic block diagram of an arithmetic decoder according to one embodiment of the present invention;
FIG. 6 shows a schematic representation of a concept for determining interval size information according to an embodiment of the present invention;
FIG. 7 shows a schematic representation of a concept for determining interval size information according to one embodiment of the present invention;
FIG. 8 shows a schematic representation of a concept for determining interval size information according to one embodiment of the present invention;
FIG. 9 shows a schematic representation of a concept for determining interval size information according to an embodiment of the present invention;
FIGS. 10A and 10B show schematic representations of concepts for determining interval size information according to embodiments of the present invention;
FIG. 11 shows a schematic representation of a concept for determining interval size information according to one embodiment of the present invention;
FIG. 12 shows a schematic representation of a concept for determining one or more updated state variables, according to one embodiment of the present invention;
FIG. 13 shows a schematic representation of a concept for determining interval size values according to one embodiment of the present invention;
FIG. 14 shows a schematic representation of a concept for determining an interval size value according to one embodiment of the present invention;
FIG. 14 shows a schematic representation of a concept for determining an interval size value according to one embodiment of the present invention;
FIG. 15 shows a schematic representation of a concept for determining interval size values according to one embodiment of the present invention;
FIG. 16 illustrates a schematic representation of a video decoder according to one embodiment of the present invention; and
FIG. 17 illustrates a schematic representation of a video decoder according to one embodiment of the present invention.

1. Encoder according to Fig. 1

The subsequent description of the drawings begins with a description of an encoder (FIG. 1) and a decoder (FIG. 2) of a block-based prediction codec for coding pictures of video to form an example of a coding framework within which embodiments of the present invention may be built. Individual encoders and decoders are described with respect to FIGS. 1 through 3. Now, a description of embodiments of the inventive concepts is presented together with an explanation of how such concepts may be built into the encoder and decoder of FIGS. 1 and 2, respectively, although the embodiments described with reference to the subsequent FIG. 4 and subsequent drawings may also be used to form encoders and decoders that do not operate according to the coding framework inherent in the encoder and decoder of FIGS. 1 and 2.

Embodiments according to the present invention may include a video encoder and a video decoder as described with respect to FIGS. 1 and 2. Additionally, any of the concepts disclosed herein may be used within an entropy coder (34) or an entropy decoder (50), for example, as described with respect to FIGS. 1 and 2.

FIG. 1 illustrates an apparatus for predictively coding a picture (12) into a data stream (14) using, for example, transform-based residual coding. This apparatus, or encoder, is indicated using the reference numeral 10. FIG. 2 illustrates a corresponding decoder (20), i.e., an apparatus (20) configured to predictively decode a picture (12') from a data stream (14) also using transform-based residual decoding, the apostrophe being used to indicate that the picture (12') reconstructed by the decoder (20) deviates from the picture (12) originally encoded by the apparatus (10) in terms of coding loss introduced by quantization of the prediction residual signal. Although FIGS. 1 and 2 exemplarily use transform-based predictive residual coding, embodiments of the present application are not limited to this kind of predictive residual coding. This is also true for other details, as will now be outlined, with respect to FIGS. 1 and 2.

The encoder (10) is configured to expose the prediction residual signal to a spatial-to-spectral transformation and encode the prediction residual signal thus obtained into a data stream (14). Similarly, the decoder (20) is configured to decode the prediction residual signal from the data stream (14) and expose the prediction residual signal thus obtained to a spectral-to-spatial transformation.

Internally, the encoder (10) may include a prediction residual signal generator (22) which generates a prediction residual (24) in order to measure the deviation of the prediction signal (26) from the original signal, i.e. from the picture (12). The prediction residual signal generator (22) may be, for example, a subtractor which subtracts the prediction signal from the original signal, i.e. from the picture (12). The encoder (10) then further includes a transformer (28) which exposes the prediction residual signal (24) to a spatial-to-spectral transform to obtain a spectral-domain prediction residual signal (24'), which signal is then exposed to quantization by a quantizer (32) which is also included by the encoder (10). The quantized prediction residual signal (24'') is thus coded into the bitstream (14). For this purpose, the encoder (10) optionally includes an entropy coder (34) that entropy codes the prediction residual signal, as transformed and quantized, into the data stream (14). The prediction signal (26) is generated by the prediction stage (36) of the encoder (10) based on the prediction residual signal (24''), which is encoded into the data stream (14) and decoded therefrom. For this purpose, the prediction stage (36) may internally include a dequantizer (38) for dequantizing the prediction residual signal (24'') to obtain a spectral-domain prediction residual signal (24''') corresponding to the signal (24') except for the quantization loss, as illustrated in FIG. 1, and a subsequent inverse transformer (40) for exposing the latter prediction residual signal (24''') to an inverse transform, i.e., a spectral-to-spatial transform, to obtain a prediction residual signal (24'''') corresponding to the original prediction residual signal (24) except for the quantization loss. Then, a combiner (42) of the prediction stage (36) recombines the prediction signal (26) and the prediction residual signal (24'''') to obtain a reconstructed signal (46), i.e., a restored copy of the original signal (12). The reconstructed signal (46) may correspond to the signal (12'). Then, the prediction module (44) of the prediction stage (36) generates a prediction signal (26) based on the signal (46), for example, by using spatial prediction, i.e., intra-picture prediction, and/or temporal prediction, i.e., inter-picture prediction.

2. Decoder according to Fig. 2

Similarly, the decoder (20) as illustrated in FIG. 2 may be internally composed of components that correspond to the prediction stage (36) and are interconnected in a corresponding manner. In particular, the entropy decoder (50) of the decoder (20) entropy decodes a quantized spectral-domain prediction residual signal (24'') from a data stream, wherein a dequantizer (52), an inverse transformer (54), a combiner (56) and a prediction module (58) interconnected and cooperative in the same manner as described above for the modules of the prediction stage (36) restore a restored signal based on the prediction residual signal (24''), so that the output of the combiner (56) becomes a restored signal, i.e., a picture (12'), as illustrated in FIG. 2.

Although not specifically described in the preceding section, it will be readily apparent that the encoder (10) may set some coding parameters, including for example prediction modes, motion parameters and the like, according to some optimization scheme, for example in terms of some rate and variance-related criteria, i.e. in a way that optimizes the coding cost. For example, the encoder (10) and the decoder (20) and the corresponding modules (44, 58) may each support different prediction modes, such as intra-coding mode and inter-coding mode. The granularity with which the encoder and the decoder switch between these types of prediction modes may correspond to subdividing each of the pictures (12 and 12') into coding segments or coding blocks. In the units of these coding segments, for example, the picture may be subdivided into blocks that are intra-coded and blocks that are inter-coded. Intra-coded blocks are predicted based on spatially already coded/decoded neighbors of individual blocks, as described in more detail below. There are several intra-coding modes, including directional or angular intra-coding modes, that can be selected for individual intra-coded segments, and according to these coding modes, sample values of neighbors along a specific direction specific to each directional intra-coding mode are extrapolated to result in individual intra-coded segments. The intra-coding mode may further comprise one or more additional modes, for example a DC coding mode and/or a planar intra-coding mode, according to which the prediction of an individual intra-coded block assigns a DC value to all samples within the individual intra-coded segment, and according to the planar intra-coding mode the prediction of an individual block is approximated or determined such that the spatial distribution of sample values is described by a two-dimensional linear function over sample positions of the individual intra-coded block, while driving a tilt and offset defined by the two-dimensional linear function based on neighboring samples. In comparison to these, an inter-coded block can be predicted, for example, temporally. For inter-coded blocks, motion vectors may be signaled in the data stream, the motion vectors indicating the spatial displacement of a portion of a previously coded picture of the video to which the picture (12) belongs, from which a previously coded/decoded picture is sampled, in order to obtain a prediction signal for the individual inter-coded blocks. In addition to the residual signal coding included in the data stream (14), such as entropy-coded transform coefficient levels representing a quantized spectral-domain prediction residual signal (24''), the data stream (14) may have encoded therein optional additional parameters, such as coding mode parameters for specifying a coding mode for the various blocks, prediction parameters for some of the blocks, e.g. motion parameters for the inter-coded segments, and parameters for controlling and signaling the subdivision of each of the pictures (12 and 12') into segments. The decoder (20) uses these parameters to subdivide the picture in the same way as the encoder did, assigning the same prediction mode to the segments and performing the same prediction to obtain the same prediction signal.

3. Functionality according to Fig. 3

Figure 3 illustrates the relationship between the restored signal on one side, i.e. the restored picture (12'), and the combination of the prediction residual signal (24'''') and the prediction signal (26) as signaled in the data stream (14) on the other side. As already indicated above, the combination may be a summation. The prediction signal (26) is illustrated in Figure 3 as subdividing the picture region into intra-coded blocks, which are exemplarily indicated using hatching, and inter-coded blocks, which are exemplarily indicated without hatching. The subdivision may be any subdivision, for example a regular subdivision that divides the picture area into rows and columns of square or non-square blocks, or a multi-tree subdivision from the picture (20) that divides the picture area into a plurality of leaf blocks of varying sizes from a tree root block, for example a quadtree subdivision, or the like, a mixture of these is exemplified in FIG. 3 , in which case the picture area is first subdivided into rows and columns of a tree root block, which is then further subdivided into one or more leaf blocks according to a recursive multi-tree subdivision.

In other words, the data stream (14) may have an intra-coding mode coded therein for the intra-coded block (80), which specifies one of several supported intra-coding modes to an individual intra-coded block (80). For an inter-coded block (82), the data stream (14) may have one or more motion parameters coded therein. Generally speaking, the inter-coded block (82) is not limited to being temporally coded. Alternatively, the inter-coded block (82) may be any block predicted from a previously coded portion beyond the current picture (12) itself, such as a previously coded picture of the video to which the picture (12) belongs, or from another scene or a hierarchically lower layer picture if the encoder and decoder are capable of scaling, respectively.

In Fig. 3, the prediction residual signal (24'''') is also illustrated by subdividing the picture area into blocks (84). These blocks may be referred to as transform blocks in order to distinguish them from the coding blocks (80 and 82). Consequently, Fig. 3 illustrates that the encoder (10) and the decoder (20) may use two different subdivisions of the picture (12) and the picture (12') into blocks, namely, one subdivision into each of the coding blocks (80 and 82), and the other subdivision into each of the transform blocks (84). The subdivisions of both may be identical, i.e. each of the coding blocks (80 and 82) may form a transform block (84) simultaneously, but FIG. 3 illustrates, for example, the case where the subdivision into the transform block (84) forms an extension of the subdivision into the coding blocks (80, 82), such that any boundary between any two of the blocks (80 and 82) overlays the boundary between the two blocks (84), or in other words, each of the blocks (80, 82) coincides with one of the transform blocks (84) or coincides with a cluster of transform blocks (84). However, the subdivisions may also be determined or selected independently of one another, such that the transform block (84) may alternatively intersect the block boundary between the blocks (80, 82). With respect to the subdivision into transform blocks (84), similar statements hold for the subdivision into blocks (80, 82), namely, that the blocks (84) may be the result of a regular subdivision of the picture region into blocks (which may or may not be arranged in rows and columns), may be the result of a recursive multi-tree subdivision of the picture region, or a combination of these or any other kind of blockation. Additionally, the blocks (80, 82 and 84) are not limited to being square, rectangular or any other shape.

Figure 3 further illustrates that a reconstructed signal (12') is directly obtained by combining a prediction signal (26) and a prediction residual signal (24''''). However, it should be noted that two or more prediction signals (26) may be combined with a prediction residual signal (24'''') to form a picture (12') according to an alternative embodiment.

In Fig. 3, the transform block (84) will have the following importance. The transformer (28) and the inverse transformer (54) perform their transforms in units of these transform blocks (84). For example, many codecs use some kind of DST or DCT for all the transform blocks (84). Some codecs may skip the transform, thereby allowing the prediction residual signal to be coded directly in the spatial domain for some of the transform blocks (84). However, according to the embodiments described below, the encoder (10) and the decoder (20) are configured in such a way that they support several transforms. For example, the transforms supported by the encoder (10) and the decoder (20) may include:

- DCT-II (or DCT-III), where DCT stands for Discrete Cosine Transform.

- DST-IV, where DST stands for Discrete Sine Transform

- DCT-IV

- DST-VII

- Identity Transformation (IT)

Naturally, the transformer (28) will support all forward versions of these transformations, but the decoder (20) or inverse transformer (54) will support the corresponding backward or inverted versions of these:

- Inverse DCT-II (or inverse DCT-III)

- Reverse DST-IV

- Reverse DCT-IV

- Station DST-VII

- Identity Transformation (IT)

The following description provides additional details on what transforms may be supported by the encoder (10) and decoder (20). In any case, the set of supported transforms may include only one transform, such as a spectral-to-spatial transform or a spatial-to-spectral transform.

As already outlined above, FIGS. 1 to 3 are presented as examples of how the further hereinafter described concepts of the present invention may be implemented to form specific examples of encoders and decoders according to the present application. As for the encoder and decoder of FIGS. 1 and 2, each of them may represent a possible implementation form of the encoder and decoder described herein below. However, FIGS. 1 and 2 are only examples. However, an encoder according to an embodiment of the present application may perform block-based encoding of a picture (12) using the concepts described in more detail below, and may differ from the encoder of FIG. 1, for example in that it is not a video encoder but still a picture encoder, in that it does not support inter-prediction, or in that the sub-division into blocks (80) is performed in a different way than illustrated in FIG. 3. Similarly, a decoder according to an embodiment of the present application may perform block-based decoding of a picture (12') from a data stream (14) using the coding concepts described in more detail below, but may differ from the decoder (20) of FIG. 2, for example in that it is not a video decoder but still a picture decoder, in that it does not support intra-prediction, or in that it sub-divides the picture (12') into blocks in a different way than described with respect to FIG. 3, and/or in that it does not derive the prediction residual from the data stream (14) in the spatial domain, for example, rather than in the transform domain.

4. Arithmetic encoder according to Fig. 4

FIG. 4 illustrates a schematic block diagram of an arithmetic encoder according to one embodiment of the present invention.

The arithmetic encoder (400) according to FIG. 4 can be used, for example, in a video encoder. However, optionally, the arithmetic encoder (400) can also be used in an audio encoder, an image encoder, an encoder for encoding coefficients of a neural network, and the like.

The arithmetic encoder (400) is configured to receive a symbol to be encoded (410), where the symbol to be encoded (410) can be represented by a symbol value. Furthermore, the encoder (400) typically also receives context information (412), which can describe, for example, what type of information is represented by the symbol to be encoded (410). For example, the context information (412) can be represented by a context index k, which describes, for example, what type of side information is described by the symbol to be encoded (410) or what type of transform coefficient is encoded by the symbol (410).

Furthermore, the arithmetic encoder (400) is configured to provide a bit stream (420), which represents a symbol (410) to be encoded or a sequence of symbols (410) to be encoded.

The arithmetic encoder (400) comprises an arithmetic encoding core or arithmetic encoder core (430), which receives a symbol (410) to be encoded and provides a bit stream (420) based thereon. The arithmetic encoding core or arithmetic encoder core (430) typically receives interval size information, which indicates, for example, the size of a subinterval (a portion of a total coding interval) into which a symbol (e.g., the least likely symbol) is mapped. Furthermore, the arithmetic encoding core or arithmetic encoder core further provides coding interval size information (434), which describes the current coding interval size (e.g., the total size of the coding interval). It should be noted that the coding interval size (434) may vary over time depending on the symbol (410) being encoded (or, more precisely, depending on the sequence of symbols (410) being encoded).

The coding interval size may vary, for example, due to a re-scaling operation performed during the arithmetic encoding process. For example, the arithmetic encoding core may perform functionality described in the High Efficiency Video Coding (HEVC) standard (H.265), for example.

The arithmetic encoder (400) further comprises a coding interval size determination unit or coding interval size determiner (440). The coding interval size determination unit (440) receives a symbol to be encoded (410) or at least one previously encoded symbol, and preferably (but not necessarily) further receives context information (412). Furthermore, the interval size determination unit (440) receives coding interval size information (434). The interval size determination unit (440) provides interval size information (432) to be used by the arithmetic encoding core (430) based on the coding interval size information, the symbol to be encoded (410) (or at least one previously encoded symbol), and optionally the context information (412).

In relation to the functionality of the concept according to Fig. 4, it should be noted that the interval size determination unit (440) is responsible for updating the interval size information (432) (continuously, for example for each new symbol to be encoded). During this update, statistics of previously encoded symbols are taken into account. Furthermore, the coding interval size information (434) provided by the arithmetic encoding (430) is also taken into account, since the interval size information (432) is preferably provided with an appropriate relevance to the coding interval size information (434). In this context, the coding interval size information (434) can for example represent the current size of the (total) coding interval (which can be caused by occasional re-normalizations of the coding intervals), whereas the interval size information (432) can for example describe the size of a portion within the (total) coding interval that is associated with a particular symbol (e.g. the least probable symbol). Therefore, the interval size information is typically smaller than the coding interval size information (434), because the coding interval size information (434) represents the size of the total coding interval, whereas the interval size information (434) represents the size of a portion of the coding interval associated with a particular symbol. As a result, the interval size information (432) is typically scaled according to the coding interval size information (434), where the scaling may optionally include somewhat non-linear behavior to avoid situations where the coding becomes very inefficient.

In addition, to conclude, by determining an appropriate interval size information (432) while considering the total size of the coding interval (represented by the coding interval size information (434)) and the statistics (and context) of previously encoded symbols, the arithmetic encoding can be performed in an efficient manner, and here, considering the statistics of previously encoded symbols helps to improve the coding efficiency.

However, it should be noted that the arithmetic encoder (400) according to FIG. 4 may be used in any of the signal encoders disclosed herein (e.g., a video encoder). Furthermore, it should be noted that the arithmetic encoder (400) according to FIG. 4 may be optionally supplemented by any of the features, functionality and details described herein. In particular, the interval size determination unit (440) may use any of the concepts disclosed herein, either taken individually or in combination.

In conclusion, the arithmetic encoder (400) according to FIG. 4 may be optionally supplemented by any of the features, functionality and details disclosed herein, taken individually or in combination.

5. Arithmetic decoder according to Fig. 5

FIG. 5 illustrates a schematic block diagram of an arithmetic decoder (500) according to one embodiment of the present invention. The arithmetic decoder (500) is configured to receive a bit stream (510) (corresponding to the bit stream (420)) and provide a decoded symbol (520) (or a sequence of decoded symbols (520)) based thereon. Typically, the decoded symbol (520) may correspond to a symbol to be encoded (410). Typically, the arithmetic encoder (400) and the arithmetic decoder (500), when considered together, perform lossless encoding and decoding such that a symbol (410) encoded by the arithmetic encoder (400) provides a bit stream (420), which, when decoded by the arithmetic decoder (500), enables a “perfect” restoration of the decoded symbol (520) correspondence to the symbol (410).

The arithmetic decoder (500) includes an arithmetic decoding core or arithmetic decoder core (530) that receives a bit stream and provides decoded symbols (520) based thereon. The arithmetic decoding core (530) typically provides coding interval size information (532) that can substantially correspond to coding interval size information (434) and receives interval size information (534) that can correspond to the interval size information (432). The arithmetic decoder (500) further includes a coding interval size determination unit or a coding interval size determination unit (540), which is configured to provide interval size information (534) used by the arithmetic decoding core (530) based on the coding interval size information (532) and also based on one or more decoded symbols (520). Furthermore, the coding interval size determination unit (540) may optionally use context information (550) that can describe what type of information is represented by the currently considered decoded symbol (520). Accordingly, the coding interval size determination unit (540) may determine interval size information (534) for a plurality of different “contexts,” i.e., a plurality of different types of decoded information (or different types of information to be decoded).

The arithmetic decoding core (530) can determine, for example, which sub-interval of the total coding interval (the size of which is described by the coding interval size information) the value represented by the corresponding bit stream (510) belongs to, and consequently, which symbol is represented by the corresponding bit stream. The size of the sub-interval of the total coding interval is described, for example, by the interval size information (534). For example, the interval size information (534) can describe the size of the sub-interval of the total coding interval associated with a particular symbol (e.g., the least probable symbol). Furthermore, it should be noted that the coding interval size (e.g., the size of the total coding interval) may occasionally change (or even for all decoded symbols) due to re-normalization.

In conclusion, an arithmetic decoding (500) is used to provide a decoded symbol (520) based on the bit stream (510), wherein the history of previously decoded symbols (or, more precisely, statistics of previously decoded symbols) is used to (dynamically) adjust an interval size associated with a symbol to be coded (wherein the adjusted interval size is described by the interval size information (534)). Furthermore, it should be noted that the interval size determining unit (540) can be substantially identical to, for example, the interval size determining unit (440). It should also be noted that the interval size determining unit (540) can include any of the functionalities disclosed herein. Therefore, any of the concepts for determining an interval size can be used in the interval size determining unit (540).

It should be noted that the arithmetic decoder (500) described herein may be used in any of the decoders described herein (e.g., an audio decoder or a video decoder). However, the arithmetic decoder (500) may also be used for decoding coefficients of an image or a neural network.

Generally speaking, the arithmetic decoder (500) described herein may be optionally supplemented by any of the features, functionality and details disclosed herein, taken individually or in combination.

6. Concept for determining interval size information according to Fig. 6

FIG. 6 illustrates a schematic diagram of a concept for determining interval size information, which may be used, for example, in an arithmetic encoder (400) according to FIG. 4 or an arithmetic decoder (500) according to FIG. 5. This concept (600), which may be implemented in the form of an interval size determination unit or in the form of an interval size determination unit, may be used, for example, to realize an interval size determination unit or an interval size determination unit (440), and/or may be used to realize an interval size determination unit or an interval size determination unit (540).

The interval size determination unit (600) may receive, for example, one or more symbol values (610), which may correspond to a symbol to be encoded (410), which may correspond to a previously encoded symbol, or which may correspond to one or more previously decoded symbols (520). Furthermore, the interval size determination unit (600) may optionally receive context information (612), which may have the form of a context model index k, for example. Furthermore, the interval size determination unit (600) may provide interval size information (620), which may correspond to the interval size information (432) or may correspond to the interval size information (534).

The interval size determination unit includes a state variable update unit (640), which provides one or more updated state variables (642) based on one or more previously determined state variables (644) while taking into account the symbol values (610) and optionally context information (612). The state variable update unit (640) may further take into account one or more other parameters, which may be static, for example, or may be adapted to an individual context, for example, depending on the context information. For example, the state variable update unit (640) may include one or more weighting factors, i.e., and/or may be considered. The state variable update unit (640) may optionally further consider an "offset", for example z, and a lookup table, for example A. Furthermore, the state variable update unit (640) may optionally be initialized to a starting value in response to information signaling that state variable initialization is to be performed. In the case of state variable initialization, the previously determined state variable values (644) may be ignored and the "updated" state variables (642) may be set to an initial value, which may be determined in advance, for example.

Moreover, the interval size determination unit (600) includes an interval size determination core, which determines interval size information (620) based on the updated state variable (or state variable value) (620). Furthermore, the interval size determination core (650) may consider, for example, coding interval size information (652), which may correspond to, for example, coding interval size information (432) or coding interval size information (532).

Accordingly, the interval size determination core (650) can provide interval size information describing the size of a subinterval associated with a particular symbol, based on interval size information (652) describing the overall size of a coding interval, and based on information about statistics of previously encoded or previously decoded symbols represented by one or more updated state variables (642).

However, it should be noted that the interval size determination unit (600) may also be used in the arithmetic encoder and arithmetic decoder described herein. Furthermore, the interval size determination unit (600) may be supplemented by any of the features, functionality and details disclosed herein. In particular, the state variable update may use any of the concepts disclosed herein. Furthermore, the interval size determination core may also use any of the concepts disclosed herein.

It should be noted that any of the concepts disclosed herein for state variable updating may be optionally combined with any of the concepts for interval size determination core disclosed herein. Any of the features, functionality and details disclosed herein may be optionally introduced into the concepts (600), either individually or in combination. It should be noted that any of the features, functionality and details disclosed with respect to determining interval size information (620) based on one or more updated state variables (642) may be used independently from any of the features, functionality and details described with respect to state variable updating.

7. Concept of determining interval size according to Fig. 7

Fig. 7 is a schematic representation of an interval size determination concept (700). In particular, Fig. 7 shows a concept that can take on the functionality of an "interval size determination core". In other words, the concept (700) according to Fig. 7 is suitable for providing interval size information based on updated state variables and also based on coding interval size information. However, the concept (700) according to Fig. 7 can be implemented in an interval size determination unit or in an interval size determination unit.

An interval size determination unit (700), which may be considered an "interval size determination core", receives, for example, updated state variables (710) that may correspond to updated state variables (642). Furthermore, the interval size determination unit (700) receives, for example, coding interval size information (712) that may correspond to coding interval size information (652). Optionally, the interval size determination unit (700) also uses context information, since the functionality of the interval size determination unit (700) can be adjusted depending on the context. For example, the context information can take the form of a context model index k. Therefore, specific functionality or parameters used in the interval size determination unit (700) can be adapted depending on the actual context represented by the context model index k.

The interval size determination unit (700) provides interval size information (720) that can correspond to the interval size information (620).

Therefore, the interval size determination unit (700) can replace, for example, the interval size determination core (650) described in FIG. 6.

From now on, some details of the interval size determination core (700) will be described.

It should be noted that the interval size determination core (700) includes a first processing path (730) and, alternatively, a second processing path (750). The first processing path (730) includes an (optional) scaling/rounding unit (732), which determines a first updated state variable (e.g., ) is scaled and/or rounded. For example, the scaling factor may be used for scaling the first updated state variable (value). For example, the scaling may be a multiplication by a scaling factor. For example, the rounding may be rounding down to the next integer value that is equal to or less than the result of the scaling. Similarly, the first processing path (730) may include a second (optional) scaling/rounding (734), which may be used for scaling the second updated state variable (e.g., ) with individual scaling factors (e.g., ) may include scaling the state variables to a next integer value that is equal to or smaller than the result of the scaling, and may also include rounding down to a next integer value that is equal to or smaller than the result of the scaling. Accordingly, a first scaled and rounded state variable (733) and a second scaled and rounded state variable (735) may be obtained. Furthermore, the first processing path (730) may include a first lookup table-based mapping (736), which receives the first scaled and/or rounded updated state variable (733) and further receives quantized coding interval size information (762). For example, the first lookup-table-based mapping (736) may use a two-dimensional lookup table to obtain the first interval size contribution (737). Similarly, the first signal processing path (730) may include a second lookup-table-based mapping (738) that receives the second scaled and/or rounded updated state variables (735) and the quantized coding interval size information (762), and provides the second interval size contribution (739) based thereon.

For example, the first lookup-table-based mapping (736) may use a two-dimensional lookup table, where the first lookup table index may be determined by a scaled and/or rounded first updated state variable (733), and the second lookup table index may be determined by quantized coding interval size information (762). For example, the first scaled and/or rounded updated state variable (733) may take an integer value falling within a particular range (e.g., from 0 to a maximum value, or from 1 to a maximum value, or within a range acceptable as a first table index). Similarly, the quantized interval size information (762) may take the form of an integer value that may serve as the second table index. For example, the quantized coding interval size information (762) can take the form of an integer value ranging between 0 and a maximum value, or between 1 and a maximum value (or any range of values that can serve as a second table index). In other words, both the first scaled and/or rounded updated state variable (733) and the quantized coding interval size information (762) are used as table indices for selecting elements of a lookup table used in the lookup-table-based mapping (736). Accordingly, an entry of the used lookup table is provided as a first interval size contribution (737).

However, the second lookup-table-based mapping (738) can be performed in the same manner, where the scaled and/or rounded second updated state variable (735) and the quantized coding interval size information (762) are used as two indices (e.g., i and j) to select an entry of the lookup table used in the second lookup-table-based mapping (738). Hence, the second interval size contribution (739) is obtained.

The first interval size contribution (737) and the second interval size contribution (739) can be combined in a combiner (740) to obtain a combined interval size contribution (742). The combined interval size contribution (742) can directly serve as the interval size information (720), or the interval size information (720) can be derived from the combined interval size contribution (742) using postprocessing (e.g., fixed scaling, or rounding, or the like).

In conclusion, when using the first processing path (730), the interval size information (720) can be obtained by combining the results of two or more lookup-table-based mappings (736, 738), where individual entries of the lookup tables to be used are determined based on individual updated state variables and based on the coding interval size information. Therefore, the interval size information (720) can be obtained in a very efficient manner.

Alternatively, however, processing as illustrated in the second signal processing path (750) may be performed. The processing performed by the second signal processing path is computationally more efficient, but with slightly reduced accuracy. For example, the second signal processing path (750) includes a combiner (751) in which the first updated state variables and the second updated state variables (and optionally additional updated state variables) are combined to obtain a combined updated state variable (751a). The second processing path (750) further includes an optional scaling/rounding unit (752), which corresponds, for example, to the scaling/rounding units (732, 734). Accordingly, the scaling/rounding unit (750) provides a scaled and/or rounded combined updated state variable (733), which is used to select elements during the lookup-table-based mapping (756). The lookup-table-based mapping (756) is preferably a two-dimensional mapping, in which case the first index of the lookup table is determined by the combined updated state variable (751a) or a scaled version and/or a rounded version thereof (753), and the second index of the two-dimensional lookup table is determined by the quantized coding interval size information (762). Accordingly, the lookup-table-based mapping (756) provides an interval size contribution (757), which can be used as the interval size information (752), or from which the interval size information (720) can be derived by optional postprocessing (e.g., scaling).

In conclusion, the interval size determination core (700) is configured to obtain interval size information (720) based on the updated state variables (710) and while considering the coding interval size information (712). The lookup-table-based mapping is used in the first signal processing path (720) to determine two or more interval size contributions 737, 739 used to derive the interval size information (720). The lookup-table-based mapping (756) is used in the alternative second signal processing path (750) to determine the interval size contributions (757) or the interval size information (720). By using the lookup-table-based mapping that considers both the updated state variables and the coding interval size information (712) to determine the indices of the lookup table, particularly efficient computation can be obtained, and in this case, it is possible to save multiplication operations.

It should be noted that the interval size determination core (700) according to FIG. 7 may be used in any of the arithmetic encoders and arithmetic decoders described herein. Furthermore, the interval size determination core (700) may be optionally supplemented by any of the features, functionality and details disclosed herein, taken individually or in combination.

8. Interval size determination core according to Fig. 8

FIG. 8 illustrates a schematic block diagram of an interval size determination core (800) according to one embodiment of the present invention. The interval size determination core (800) according to FIG. 8 can be used in any of the audio encoders and audio decoders disclosed herein.

The interval size determination core (800) receives updated state variables (810) and also coding interval size information (812). The updated state variables (810) may correspond to, for example, the updated state variables (710) or the updated state variables (642). The coding interval size information (812) may correspond to, for example, the coding interval size information (712) or the coding interval size information (652) or the coding interval size information (532) or the interval size information (434). Furthermore, the interval size determination core (800) provides interval size information (820), which may correspond to the interval size information (720) or the interval size information (620) or the interval size information (534) or the interval size information (432).

The interval size determination core (800) may include, for example, a determination unit (830) of a probability value (832). The probability value (832) may be obtained, for example, based on one or more updated state variables (810) and may describe, for example, a probability of a symbol to be encoded (e.g., “0” or “1”). The interval size determination core (830) further includes a determination unit (840) of a probability of a less-probable symbol (or a least-probable symbol), which may provide a probability value (842) describing the probability of the less-probable symbol or the least-probable symbol. The interval size determination core (800) further includes a quantization unit (850), which quantizes the probability value (842) to obtain a quantized probability value (852). Furthermore, the interval size determination core (800) further includes a quantization unit (860), which quantizes the coding interval size information to obtain quantized coding interval size information (862). The interval size determination core (800) further includes a mapping unit (870), which receives the quantized probability value (852) and the quantized coding interval size information (862), and maps both the quantized probability value (852) and the quantized coding interval size information (862) to the interval size information (820).

From now on, some details related to the functionality of the interval size determination core (800) will be described.

The determination unit (830) of the probability value (832) may include, for example, a first signal processing path (880) or a second signal processing path (890). It should be noted that the signal processing paths (880, 890) may be considered alternatives. The first signal processing path (880) includes a first mapping unit (882), which maps the first updated state variable (810) to a first probability value (883), for example, using a lookup table. The first signal processing path (880) further includes a second mapping unit (884), which maps the second updated state variable (810) to a second probability value (885), for example, using a lookup table. The first signal processing path (880) further comprises a combination (886) which is configured to combine the first probability value (883) and the second probability value (885), for example, using a linear combination (and optionally wherein quantization may be used) in which different scalings may be applied to the first probability value (883) and the second probability value (885). Accordingly, the combination (886) provides the probability value (832).

Alternatively, a second signal processing path (890) may be used. The second signal processing path (890) includes a combiner (892), which receives two or more updated state variables (810) and provides a combined updated state variable (893) based thereon (e.g., using linear combination). Furthermore, the second signal processing path (890) includes a mapper (894), which maps the combined updated state variable (893) to a probability value (832), for example, using a lookup table.

Therefore, it becomes possible to obtain the probability value (832) by using either the first signal processing path (880) or the second signal processing path (890), which may be considered as two different alternatives. The first signal processing path has slightly increased complexity and, therefore, slightly increased accuracy, since it has two mapping sections (882, 884). In contrast, the second signal processing path (890) has only a single mapping section and, therefore, slightly reduces complexity at the expense of slightly decreasing accuracy.

In the probability determination unit (850) of a less probable symbol, the probability of a less probable symbol can be determined by, for example, selecting a smaller value among the probability value (832) and the complement of the probability value (a value obtained by subtracting the probability value from 1). Accordingly, a probability value (842) describing the probability that a less probable symbol is obtained is obtained. This probability value (842) is obtained in the quantization unit (850), for example, by a function (.) or (.) is used to quantize. Accordingly, a quantized probability value or probability index i (852) is obtained and used in the mapping unit (870).

The quantization unit (860) of the coding interval size information (812) may provide, for example, a quantized coding interval size value (862) or a quantized coding interval size index j. However, in some cases, both the quantized coding interval size value Q _r (R) and the coding interval size index j may be obtained, and they may both be used, for example, in the mapping unit (860). The mapping unit (860) may use, for example, a mapping mechanism, which may be based on the lookup table (RangeTabLPS) described herein, and/or may be based on the lookup table (BaseTabLPS) described herein, and/or may use the lookup table (ProbTabLPS) described herein. Optionally, a scaling function Scal(.) described herein may also be used in the mapping unit (870).

In other words, there may be multiple mapping units that can be used to derive interval size information (820) based on the quantized probability value or probability index (852) and/or the quantized coding interval size (862) and/or the coding interval size index j.

Additionally, it should be noted that the quantization unit (850) may map, for example, the probability value (842) (or, alternatively, the probability value (832) if the decision unit (840) is omitted) to an integer value. Alternatively, the quantization unit (850) may map the mapped value (842) (or, alternatively, the value (832) if the decision unit (840) is optionally omitted) to the probability value (832) or to a value having a lower numeric resolution than the probability value (842). However, it is preferred that the quantized probability value (852) take the form of a probability index (e.g., i), i.e., an integer numeric representation, which may be used to designate an entry in a lookup table (e.g., RangeTabLPS).

The quantization unit (860) may have different results. The coding interval size information (812) may be quantized, for example, into quantized coding interval size information (862), which has a lower resolution than the coding interval size information (812). In other words, intervals of values of the coding interval size information (812) may be mapped to individual quantized values of the quantized coding interval size information (862), where the quantization may be linear or non-linear, for example. Alternatively or additionally, the coding interval size information may be mapped to coding interval size indices j, i.e., a continuous range of integer values, which may be used directly as table indices for selecting entries in the lookup table. However, it should be noted that in some cases, both quantized coding interval size information quantized to different values and quantized coding interval size information quantized to different indices j (i.e., to subsequent integer values) may be used.

As mentioned above, the mapping unit (870) can be implemented using different concepts described herein.

In conclusion, the interval size determination core (800) may be used in any of the arithmetic encoders and arithmetic decoders described herein. Furthermore, the interval size determination core (800) may be optionally supplemented by any of the features, functionality and details disclosed herein, taken individually or in combination.

9. Interval size determination core according to Fig. 9

FIG. 9 illustrates a schematic block diagram of an interval size determination core (900) that may be used in any of the arithmetic encoders and arithmetic decoders disclosed herein.

The interval size determination core (900) is configured to receive state variable values (910) and provide interval size information (920). Generally speaking, the interval size determination core (900) is configured to derive interval size information (920) for arithmetic encoding of one or more symbol values to be encoded (or for arithmetic decoding of one or more symbol values to be decoded) based on a plurality of state variable values (910) representing statistics of a plurality of previously encoded symbol values having different adaptation time constants. The interval size determination core (900) includes an optional first scaling and/or rounding unit (930) in which a first state variable (which may be an updated state variable) is scaled and/or rounded. The interval size determination core (900) further includes an optional second scaling and/or rounding unit (934) in which a second state variable is scaled and/or rounded. Accordingly, the optional first scaling and/or rounding unit provides a first scaled and/or rounded state variable (932), and the optional second scaling and/or rounding unit (934) provides a second scaled and/or rounded state variable (934).

The interval size determination core (900) further includes a first mapping unit (940) using a lookup table. The first mapping unit (940) maps the first state variable, or a scaled version and/or a rounded version (932) of the first state variable, using a lookup table (e.g., a two-dimensional lookup table defining R LUT1 for a plurality of different values of the lookup table LUT1 or R). Accordingly, a first probability value (942) is obtained by the first mapping unit (940). The interval size determination core (900) further includes a second mapping unit (950) which maps the second state variable, or a scaled version and/or a rounded version (934) thereof, to a lookup table (e.g., a two-dimensional lookup table defining R LUT1 for a plurality of different values of the lookup table LUT1 or R). A two-dimensional lookup table (LUT1) is used to map the second probability value (952). Accordingly, the second probability value (952) is obtained by the second mapping unit (950) based on the second state variable value, or based on a scaled version and/or a rounded version thereof (934).

Finally, interval size information (920) is obtained based on the first probability value (942) and the second probability value (952).

However, it should be noted that the determination of the first probability value (942) and the second probability value (952) should only be considered as examples of what quantities can be obtained when using the first mapping unit (940) and the second mapping unit (950). Conversely, it may be possible to further derive other quantities, such as contributions to the interval size information (920), by using the first mapping unit (940) and the second mapping unit (950).

However, it should be noted that the interval size determination core (900) described in FIG. 9 may be used in any of the arithmetic encoders and arithmetic decoders disclosed herein. Furthermore, it should be noted that the interval size determination core (900) may be optionally supplemented by any of the features, functionality and details described herein, either individually or in combination.

10. Determining the interval size according to Fig. 10a and Fig. 10b

Figure 10a shows a schematic representation of a concept for determining interval size information, which may be used, for example, in an interval size determination core.

As illustrated, the concept of FIG. 10a receives a plurality of state variable values (1010a, 1010b), which may correspond to the state variable value (910) or may be updated state variable values. Furthermore, the concept (1000) provides interval size information (1020), which may correspond to the interval size information (920). The concept (1000) includes a first mapping unit (1040), which maps the first state variable value (1010a) (or a scaled version and/or a rounded version thereof) to a first probability value (1042), which may correspond to the first probability value (942). Furthermore, the concept (1000) includes a second mapping unit (1050) that maps the second state variable value (1010b) (or a scaled and/or rounded version thereof) to a second probability value (1052). Furthermore, the concept (1000) includes a combination of the first probability value (1042) and the second probability value (1052), wherein the combination can be performed using, for example, Equation 7. Accordingly, the combination unit (1060) provides a combined probability value (1062). Furthermore, the concept (1000) includes a multiplication unit (1070) of the combined probability value (1062), wherein the multiplication can be performed using a coding interval size value R. Accordingly, the interval size information (1020) is obtained by the multiplication (1070) of the combined probability value (1062a) and the coding interval size value R. The interval size information (1020) can describe, for example, the size of the coding interval associated with a less probable symbol or a least probable symbol (or, alternatively, the size of the coding interval associated with a more probable symbol or a most probable symbol). Optionally, this concept (1000) can include a mechanism for deriving the probability of the less probable symbol or the least probable symbol (e.g., between the combiner (1060) and the multiplier (1070)), or can include a mechanism for deriving the interval size information associated with the less probable symbol or the least probable symbol based on the result of the multiplier (1070).

Therefore, the concept (1000) according to Fig. 10a can implement the functionality as described for Fig. 9.

However, it should be noted that this concept (1000) can be used in any of the arithmetic encoders and arithmetic decoders disclosed herein.

Additionally, these concepts (1000) may be optionally supplemented by any of the features, functionality and details disclosed herein, taken individually or in combination.

FIG. 10b illustrates a schematic block diagram of a concept (1080) for providing interval size information (1084) based on a first state variable value (1082a) and a second state variable value (1082b). The concept (1080) includes mapping (1085a) the first state variable value (1082a), or a scaled and/or quantized version thereof, to a first interval size contribution (1086a). Furthermore, the concept (1080) includes a second mapping (1085b), which maps the second state variable value (1082b), or a scaled and/or quantized version thereof, to a second interval size contribution (1086b).

The first mapping (1085a) and the second mapping (1085b) may perform the mapping using, for example, a two-dimensional lookup table. The two-dimensional lookup table may, for example, define a product between a one-dimensional lookup table (e.g., LUT1) for a plurality of different values of the coding interval size information R and R. In other words, each row or each column of the two-dimensional lookup table used in the mapping (1085a) may define a product between a lookup table (LUT1), as described herein, and a respective coding interval size value associated with the row or column. The same holds true for the two-dimensional lookup table used in the second mapping (1085b), wherein the lookup table may be the same as the lookup table used in the first mapping (1085a) or may be different from the lookup table. Furthermore, it should be noted that the coding interval size information can be used to select elements of appropriate two-dimensional lookup tables within the first mapping (1085a) and the second mapping (1085b) (wherein, for example, the first lookup table index can be based on individual state variable values and the second lookup table index can be based on coding interval size values (or their quantized version Qr(R)).

Accordingly, the interval size information (1084) can be obtained with very low computational complexity. Furthermore, it should be noted that between the mappings (1085a, 1085b) and the combining portion (1088) where the interval size contributions (1086a, 1086b) are combined, appropriate processing may be inserted to determine the contribution of the interval associated with the least probable symbol or the least probable symbol to the interval size. However, alternatively, postprocessing to determine the interval size for the least probable symbol or the least probable symbol based on the result of the combining (1088) of the interval size contributions (1086a, 1086b) may be inserted after the combining portion (1088).

In conclusion, the concept (1080) according to Fig. 10b can be used to derive interval size information (1086) based on state variable values (1082a, 1082b) and also depending on coding interval size information or coding interval size values.

Moreover, it should be noted that this concept (1080) can be used in any of the arithmetic encoders and arithmetic decoders disclosed herein.

Furthermore, it should be noted that the concept (1080) of FIG. 10b may be optionally supplemented by any of the features, functionality and details described herein, taken individually or in combination.

11. Interval size determination core according to Fig. 11

FIG. 11 illustrates a schematic block diagram of an interval size determination core (1100) according to one embodiment of the present invention.

An interval size determination core receives a plurality of (typically updated) state variable values (1110) and provides interval size information (1120) based thereon. Generally speaking, the interval size determination core (1100) is configured to derive interval size information for arithmetic encoding of one or more symbol values to be encoded (or for arithmetic decoding of one or more symbol values to be decoded) based on a plurality of state variable values (1110) representing statistics of a plurality of previously encoded (or previously decoded) symbol values having different adaptation time constants. The interval size determination core (1100) includes a combination/combiner (1130) configured to derive a combined state variable value (1132) based on the plurality of state variable values (1110). Optionally, the interval size determination core (1100) includes a scaling and/or rounding unit (1140) that scales and/or rounds the combined state variable value (1132) to obtain a scaled and/or rounded combined state variable value (1142). Furthermore, the interval size determination core (1100) includes a lookup table-based mapping unit (1150) that is configured to map the combined state variable value (1132), or a scaled version and/or a rounded version thereof (1142), using a lookup table to obtain interval size information describing interval sizes for arithmetic encoding/decoding (e.g., for example, intervals associated with particular symbols, such as less-significant symbols or more-significant symbols). However, optionally, post-processing (1160) may be used to derive interval size information (1120) based on the results (1152) of the lookup-table-based mapping unit (1150).

It should be noted that the interval size determination core (1100) may be used in any of the arithmetic encoders and arithmetic decoders disclosed herein. Furthermore, it should be noted that the interval size determination core (11) may be optionally supplemented by any of the features, functionality and details described herein.

12. Update state variables according to Fig. 12

FIG. 12 illustrates a schematic block diagram of a state variable update according to one embodiment of the present invention. A state variable update unit (1200) (which may also be considered a state variable updater) is configured to receive a symbol value (1210), which may be a symbol value of a symbol to be encoded or a symbol value of a previously decoded symbol (or a symbol value of a previously encoded symbol). Furthermore, the state variable update unit (1200) may be configured to receive one or more previously determined state variable values (1212) and provide one or more updated state variable values (1220). In particular, the state variable update unit (1200) may be configured to update a first state variable value depending on a symbol value (e.g., representing a symbol to be encoded or a previously encoded symbol or a previously decoded symbol) and using a lookup table. In other words, the state variable update unit (1210) may include a lookup-table-based state variable update unit or a lookup-table-based state variable update unit (1230). Therefore, the updated state variable value may be provided based on a corresponding previously determined state variable value and by considering a symbol value based on a symbol to be encoded or a previously encoded symbol or a previously decoded symbol.

Accordingly, the state variable update unit (1200) may provide one or more updated state variable values. If multiple updated state variable values are to be determined, the lookup-table-based state variable update may be performed individually for each state variable value (however, here, the same mechanism and/or the same lookup table may be used, which may have different scaling parameters and/or quantization functionality).

However, the state variable update unit (1200) described herein may be used in any of the arithmetic encoders and arithmetic decoders disclosed herein. Furthermore, however, it should be noted that the state variable update unit (1200) may be optionally supplemented by any of the features, functionality and details described herein, either individually or in combination.

13. Interval size determination core according to Fig. 13

FIG. 13 illustrates a schematic block diagram of an interval size determination core (1300) according to one embodiment of the present invention.

The interval size determination core receives one or more state variable values (1310), which may be, for example, updated state variable values. Furthermore, the interval size determination core provides an interval size value (1320) based on the one or more state variable values (1310).

The interval size determination core includes a lookup table evaluation mechanism (1330), which receives a probability index (1332), which may be based on one or more state variable values (1310), and provides an interval size value (1320).

For example, a probability index (1332) can be derived from one or more (updated) state variable values using a probability index derivation unit (1340) (which may include a scaling unit and/or a rounding unit and/or a quantization unit).

For example, one or more updated state variable values (1310) may be determined in an arithmetic encoder or arithmetic decoder disclosed herein and may represent statistics of a plurality of previously encoded symbol values.

Generally speaking, the interval size determination core (1300) is configured to determine an interval size value (1320) using a base lookup table (1350). The lookup table evaluation mechanism can be configured to determine the interval size value (1320) such that if a selected probability index (1332) based on one or more state variable values is within a first range, the determined interval size value is equal to an element (1350) of the base lookup table or a rounded version (1350) of the element of the base lookup table, and if the probability index (1332) is within a second range, the determined interval size value is obtained using scaling (1360) (and optionally rounding) of the element (1350) of the base lookup table. Accordingly, the interval size value (1320) can be used to perform arithmetic encoding or arithmetic decoding of one or more symbols.

In other words, for example, as illustrated in FIG. 8 (the first signal processing path (880) or the second signal processing path (890) in combination with the optional decision unit (840) and the quantization unit (850)), a probability index (1332) that can be derived from one or more (updated) state variable values can be used to determine whether an entry in the base lookup table is used "as is" or scaled (1360) (which can be determined by the probability index (1332)).

In other words, the probability index (1332) may determine both which element (1350) of the base lookup table is selected, as schematically indicated by reference numeral 1370, and whether scaling of such selected entry of the base lookup table (1350) is performed, as schematically indicated by reference numeral 1380. For example, the selection of an entry of the base lookup table (1370) may be determined by one or more of the least significant bits of the probability index (1332), and the determination of whether scaling (1360) is performed may be based on one or more of the most significant bits of the probability index (1332). However, rather than evaluating a group of bits, the selection of an entry in the base lookup table (1350) may be determined by the remainder of a division of the probability index (1332) by a predetermined value, and the determination of whether scaling (1360) is performed may be made based on a determination of which of a plurality of ranges the currently considered probability index value falls within.

Furthermore, it should be noted that optionally, for example if the base lookup table is a two-dimensional table, the coding interval size information (e.g., R) may be considered in selecting an entry of the base lookup table (1350). In another optional alternative, the coding interval size information (e.g., R) may be used to determine whether additional scaling depending on the coding interval size information should be performed (e.g., applied to a selected entry of the base lookup table) to obtain the interval size value (1320).

However, it should be noted that the interval size determination core (1300) described herein may be used in any of the arithmetic encoders and arithmetic decoders disclosed herein to derive interval size values.

Furthermore, it should be noted that the interval size determination core (1300) may optionally be supplemented by any of the features, functionality and details described herein.

14. Interval size determination core

FIG. 14 illustrates a schematic block diagram of an interval size determination core (1400) according to one embodiment of the present invention.

The interval size determination core (1400) receives one or more state variable values (1410), which may be, for example, updated state variable values. Furthermore, the interval size determination core (1400) provides an interval size value (1420) based on the one or more state variable values (1410).

The interval size determination core (1400) includes a lookup table evaluation mechanism (1430), which receives a probability index (1432) that may be based on one or more state variable values (1410), and provides interval size information or an interval size value (1420).

For example, a probability index (1432) can be derived from one or more (updated) state variable values using a probability index derivation unit (1440).

For example, one or more updated state variable values (1410) may be determined in an arithmetic encoder or an arithmetic decoder disclosed herein and may represent statistics of a plurality of previously encoded symbol values and/or a plurality of previously decoded symbol values.

Generally speaking, the interval size determination core (1400) is configured to determine an interval size value (1420) based on probability values (e.g., probability indices (1432)) derived from one or more state variable values (1410) using a probability table (e.g., ProbTabLPS) and based on a coding interval size (e.g., described by the coding interval size information (1412)). For example, the probability table (1450) describes an interval size for a set of a plurality of different probability values (or probability indices (1432)) and for a given coding interval size (e.g., for a given reference coding interval size). As illustrated in FIG. 14, the probability indices (1432) can be used, for example, to select which element of the probability table should be used as a basis for providing the interval size value (1420). In other words, the probability index (1432) determines the selection of an element of the probability table for further processing. Furthermore, the probability index (1432) by which the selected entry of the probability table is scaled in the scaling unit (1460) is determined by its value. Generally speaking, if the current probability value is not a set of multiple probability values and/or the current coding interval size is different from a given (reference) coding interval size, the interval size determination core may be configured to scale an element or entry of the probability table (e.g., an element selected depending on the current probability value or the probability index (1432)). In other words, the interval size value (1420) may be derived from the selected entry of the probability table (1450) using the scaling unit (1460), where the scaling unit may depend on both the probability value or the probability index (1432) and the coding interval size information (1412).

For example, an entry in the probability table (1450) may be associated with a given coding interval size and a given range of probability values or probability indices (wherein this range may typically cover three or more different probability values or probability indices, and the number of entries in the probability table is preferably a potentiometer of 2 to facilitate computational operations). If the coding interval size (1412) is different from the reference coding interval size to which the entry in the probability table (1450) is associated, the scaling unit (1460) may, for example, scale the selected entry in the probability table (1460). In other words, if the actual coding interval size (1412) is different from the reference coding interval size (e.g., the coding interval size to which an entry of the probability table (1450) is associated), the scaling unit (1460) may take this deviation into account (at least if the deviation between the reference coding interval size and the actual coding interval size (1410) exceeds the size of the quantization interval used to quantize the coding interval size). Furthermore, the scaling unit (1460) may also take into account whether the probability value or probability index (1432) is outside the range of probability values or probability indices to which an entry of the probability table (1450) is associated. For example, if an entry in the probability table (1450) is associated with a first range of probability indices, but the actual probability index (1432) falls within a second range of indices that does not overlap with the first range of probability indices, the scaling unit (1460) may take this finding into account and consider additional scaling (in addition to scaling based on the deviation of the actual coding interval size from the reference coding interval size).

In conclusion, if the probability value or probability index (1432) belongs to a set of multiple probability values for which no probability table entry is provided, and the actual coding interval size (1412) is equal to the reference coding interval size (or is quantized to a value equal to the reference coding interval size), the interval size determination core (1400) can provide the selected entry of the probability table (1450) as the interval size value (1420). On the other hand, if the probability value or probability index (1432) belongs to a set of multiple probability values for which a probability table entry is provided and/or the actual coding interval size (1412) deviates from the reference coding interval size (e.g., deviates by a value equal to the actual coding interval size being quantized to a different value), the scaling unit (1460) scales the selected entry of the probability table (1450) to obtain the interval size value (1420).

Accordingly, the interval size value (1420) can be obtained using a relatively small lookup table (1450), which may be, for example, a one-dimensional probability table, the number of entries of which is smaller than the number of different possible probability values or probability index values (e.g., at least by a factor of 2).

However, it should be noted that the interval size determination core (1400) may optionally be supplemented by any of the features, functionality and details described herein. Furthermore, it should be noted that the interval size determination core (1400) may optionally be used within any of the arithmetic encoders or arithmetic decoders disclosed herein, and within any of the video encoders or video decoders disclosed herein.

15. Interval size determination core according to Fig. 15

FIG. 15 illustrates a schematic block diagram of an interval size determination core (1500) according to one embodiment of the present invention.

The interval size determination core (1500) is configured to receive one or more state variable values, which may be, for example, updated state variable values. For example, the one or more state variable values (1510) may include combined state variable values. Furthermore, the interval size determination core (1500) is configured to provide an interval size value (1520), which may be, for example, a subinterval width value, for example, R _LPS .

The interval size determination core (1500) comprises an optional mapping unit and/or rounding unit, which is used to determine a single state variable value representing statistics of a plurality of previously processed (e.g., previously encoded or previously decoded) symbol values. Generally speaking, the arithmetic encoder is configured to compute a subinterval width value (e.g., an interval size value (1520)) for arithmetic encoding or arithmetic decoding of a symbol value to be encoded or a symbol value to be decoded, from a combined state variable value (e.g., from an updated combined state variable value (1510)), or from a scaled version and/or a rounded version thereof. The interval size determination core (1500) comprises a one-dimensional lookup table (1550), which is used to map, for example, a single state variable value (e.g., a combined state variable value), or a scaled version and/or a rounded version thereof, to a probability value. For example, an entry of the one-dimensional lookup table (1550) includes a probability value for a different value interval of the value domain for the associated state variable value. Furthermore, the interval size determination core includes a quantization unit (1560), which is configured to quantize the coding interval size information (1512) describing the size of a coding interval of an arithmetic encoding or an arithmetic decoding (e.g., the size prior to the arithmetic encoding of the symbol value to be encoded, or prior to the arithmetic decoding of the symbol value to be decoded) into a quantization level. Accordingly, the quantized coding interval size information (1562) is provided. Furthermore, a scaling unit/multiplication unit (1570) is present, which determines a product between the probability value and the quantization level (or, more precisely, the quantized coding interval size information (1562)) (e.g., using a lookup of a precomputed product, or using a multiplication). For example, the probability values are provided by selecting entries of a one-dimensional lookup table (1550) depending on the state variable values or their scaled and/or rounded versions. These probability values (1552) can then be scaled depending on (quantized) coding interval size information (1562) (i.e. depending on the "quantization level"), where the scaling can correspond to determining the product between the probability values and the quantization level. Accordingly, the interval size values (1520) are provided in an efficient manner, and the use of a one-dimensional lookup table is sufficient.

Furthermore, it should be noted that the interval size determination core (1500) described herein may be optionally supplemented by any of the features, functionality and details described herein, either individually or in combination. Furthermore, it should be noted that the interval size determination core (1500) may now be optionally used within any of the arithmetic encoders or arithmetic decoders described herein, and within any of the video encoders or video decoders described herein.

16. Video decoder according to Fig. 16

FIG. 16 illustrates a schematic block diagram of a video decoder (1600) according to one embodiment of the present invention.

A video decoder (1600) is configured to receive encoded video information and provide decoded video information (or decoded video content) based thereon.

The encoded video information (1610) (which may be considered a video bitstream) may include, for example, slice-type information and may further include an encoded representation of a binary sequence. Optionally, the encoded video information (1610) may include additional information, although this is not essential to the present invention.

Generally speaking, a video decoder is configured to decode a plurality of video frames (e.g., a sequence of video frames), and the video decoder can be configured to decode a video frame, for example, subdivided into a set of one or more slices (preferably, the plurality of slices). The video decoder can be configured to select a mode of operation for decoding a slice by evaluating slice type information, for example, which is included in the encoded video information (1610) and indicates whether the slice is encoded using an independent coding mode in which there is no prediction of the video content of the current frame based on a previous frame, or using a single-predictive mode in which there is prediction of a block of pixels based on a single block of pixels of a previous frame, or using a bi-predictive mode in which there is prediction of pixels based on two or more blocks of pixels of one or more previous frames (this can be performed, for example, by a "video restoration" block (1680)).

The video decoder (1600) includes an arithmetic decoder (1620) configured to provide a decoded binary sequence (1622) (to be used in a "video restoration" block), for example, based on an encoded representation of a binary sequence included in encoded video information (1610). The arithmetic decoder preferably includes a first source statistics value determination unit (1630) and a second source statistics value determination unit (1640). Accordingly, the arithmetic decoder (1620) is configured to determine a first source statistic value (1632) (e.g., a first state variable value) using a first window size (or using a first time constant) (wherein, for example, a state variable update as described herein may be used) and to determine a second source statistic value (1642) (e.g., a second state variable value) using a second window size (or using a second time constant) (wherein, for example, a state variable update as described herein may be used). Additionally, the arithmetic decoder optionally includes a combining unit (1650). Accordingly, the arithmetic decoder can be configured to determine a combined source statistic value (1652) (e.g., a combined state variable value) based on the first source statistic value and based on the second source statistic value.

Moreover, the arithmetic decoder (1620) preferably includes a range value determination unit (1660) (which may include, for example, any of the interval size determination cores described herein, or the interval size determination units described herein). Accordingly, the arithmetic decoder may be configured to determine one or more range values (or interval size information as described herein) for the interval sub-segmentation, which are used to map an encoded representation of a binary sequence (included in the encoded video information (1610)) to a decoded binary sequence (1622) (which is used by the video restoration block (1680)) based on the combined source statistics values (1652) (or based on the first and second source statistics values).

Preferably, the arithmetic decoder (1620) further comprises an arithmetic decoding core (1670) (which may be, for example, a block or a unit), which receives one or more range values (1662) from the range value determination unit (1660) and derives a decoded binary sequence (1622) from the encoded binary sequence included in the encoded video information (1610) using these range values.

Furthermore, the video decoder comprises, for example, a video restoration block (or unit) (1680), which receives a decoded binary sequence (1622) and provides decoded video content (1612) based on the decoded binary sequence (1622) (preferably taking into account additional control information, e.g. slice-type information).

In conclusion, the arithmetic decoder (1600) receives encoded video information (1610) and performs decoding of an encoded representation of a binary sequence to derive a decoded binary sequence (1622). Arithmetic decoding utilizes knowledge of the probabilities of binary values within the decoded binary sequence (1622). This knowledge of the probabilities (or estimated probabilities) of binary values within the decoded binary sequence (1622) is taken into account by the arithmetic decoding core (1670) by relying on a range value (1662) that defines interval subdivisions. In brief, the arithmetic decoding core can use the range value (1662) to define different intervals (e.g., between zero and 1, or over a range of integer values). An arithmetic decoding core may, for example, interpret an encoded representation of a binary sequence as a representation of a number falling within one of the intervals defined using these range values. By recognizing which of the intervals a number represented by the encoded representation of the binary sequence falls within, the arithmetic decoding core (1670) may determine which bits or which bit sequences were encoded using the encoded representation of the binary sequence.

However, it should be noted that this description of the arithmetic decoding core (1670) should be considered as a very brief and general description only. Details of the arithmetic decoding core can be found, for example, in the H.264 and H.265 standards. However, different concepts (concepts for the operations of the arithmetic decoding core) can also be found in these documents, and the details of the arithmetic decoding core have no specific relevance to the present invention.

However, in order to obtain well-fitted range values (which allows for high bit efficiency), the arithmetic decoder (1620) (or, more generally, the video decoder) determines the two source statistics values (1632, 1642) using different window sizes (wherein the "window size" defines the degree of smoothing across the multiple decoded binary values of the decoded binary sequence (1622)). Furthermore, in order to increase the reliability of the range values provided to the arithmetic decoding core (1670), the first source statistics value (1632) and the second source statistics value (1642) are combined in some embodiments into a combined source statistics value (1652).

Accordingly, it can be said that the video decoder (1600) provides high efficiency because the range values used by the arithmetic decoding core (1670) are well adapted to the actual probabilities of the bit values (e.g., the actual probabilities of the bit values "0" and "1" within the decoded binary sequence (1622).

Additionally, it should be noted that the video decoder (1600) may also be modified. In an alternative implementation, the second source statistics value determination unit (1640) may be replaced by providing a fixed value (which may be independent of the decoded binary sequence but may depend on one or more parameters). In such a case, the arithmetic decoder is optionally configured to combine the first source statistics value (1632) with a fixed non-zero value in order to obtain the combined source statistics value (1652). It has been found that this simplification allows for good results in some cases, and for example avoids unduly strong fluctuations in the combined source statistics value. In other words, by introducing a fixed contribution to the determination of the combined source statistics value, the combined source statistics value may no longer deviate too much from this fixed value. Accordingly, if by chance a longer sequence of the same bit values exists within the decoded binary sequence (1622), some "hindsight" that goes into the statistics of the decoded binary sequence can be used to avoid too much degradation in coding efficiency.

Additionally, it should be noted that the functionality of the arithmetic decoder (and individual blocks of the arithmetic decoder) may generally be considered as the functionality of the video decoder as a whole. In other words, functionality described as the functionality of the arithmetic decoder described herein may also be performed by other blocks of the video decoder.

Furthermore, it should be noted that the video decoder (1600) of FIG. 1 may be optionally supplemented by any of the features, functionality and details described herein, taken individually or in combination.

17. Video decoder according to Fig. 17

FIG. 17 illustrates a schematic block diagram of a video decoder (1700) according to one embodiment of the present invention.

A video decoder (1700) is configured to receive encoded video information (1710) (e.g., a video bitstream) and provide decoded video content (1712) (e.g., a sequence of video frames) based thereon. The encoded video information (1710) may include, for example, slice type information as described herein. The encoded video information (1710) may further include configuration information, which may also be considered control information. Furthermore, the encoded video information (1710) may include an encoded representation of a binary sequence.

In FIG. 17, two main blocks of the video decoder (1700) are illustrated, namely, the arithmetic decoder (1720) and the video restoration unit (1780). However, it should be noted that the distribution of the functionality of the video decoder is not limited to a fixed block structure and may vary widely. It should also be noted that the actual implementation of the video decoder may have additional blocks and/or functionality known to those skilled in the art.

The arithmetic decoder (1720) receives an encoded representation (1711) of the binary sequence. However, the arithmetic decoder (or a control block that may be external to the arithmetic decoder) may optionally receive slice type information and configuration information (or control information). In particular, the arithmetic decoder (1720) provides the decoded binary sequence (1722) to the video restoration unit (1780) based on the encoded representation (1711) of the binary sequence, while optionally considering some or all of the slice type information and the configuration information or the control information.

Hereinafter, the functionality of the arithmetic decoder (1720) will be described in more detail. The arithmetic decoder includes an arithmetic decoding core (1770), which receives an encoded representation (1711) of a binary sequence and provides a decoded binary sequence (1722). The arithmetic decoding core determines which bit values of the decoded binary sequence (1722) are represented by the encoded representation (1711) of the binary sequence. For this purpose, the arithmetic decoding core (1770) checks whether a number represented by the encoded representation (1711) of the binary sequence is included within a certain interval of a range of numbers. A particular bit value, or group of bit values, or symbol of the decoded binary sequence (1722) is recognized based on a determination as to which of the multiple (at least two) intervals contains a number represented by the encoded representation (1711) of the binary sequence.

In order to derive the decoded binary sequence (1722), the arithmetic decoding core receives information about the intervals, which typically correspond to some degree to the probabilities of the bit values. In this case, the arithmetic decoding core (1770) receives "range values" or "interval size information (1762)" used for interval subdivision (i.e., range values (1762) that serve to define the intervals of the number range to be used by the arithmetic decoding core (1770). In particular, it should be noted that the arithmetic decoding core (1770) may be similar or identical to an arithmetic decoding core used, for example, in a video encoder/decoder according to the standard H.264 or in a video encoder/decoder according to the standard H.265. However, it should be noted that different approaches may be used to realize the arithmetic decoding core (1770).

From the foregoing description, it becomes apparent that an important function of the arithmetic decoder (1720) is to provide range values or interval size information (1762) that define interval subdivisions for the arithmetic decoding core (1770). Generally speaking, the arithmetic decoder (1720) derives these range values (1762) from previously decoded binary values of the decoded binary sequence (1722), optionally taking into account some control-information that defines parameters such as, for example, initialization values, "window size", "window size adaptation", and the like.

In the arithmetic decoder (1700), two source statistics value determination blocks (or units) (1730, 1740) are used (which may correspond to, for example, the state variable update unit described herein). For example, the first source statistics value determination block (1730) receives one or more previously decoded binary values (or symbol values) of the decoded binary sequence (1722) (also designated as x _t ) and, based thereon, provides a first source statistics value (1732) (which may correspond to the first state variable value described herein). The first source statistics value determination block may receive, for example, a constant or variable BITS _a that specifies the number of bits used to represent some configuration information, such as the source statistics value (1732), and a constant or variable n _a that specifies a "window size" to be used by the source statistics value determination block (1730), and/or any other parameter described herein. For example, the first source statistics value determination block (1730) may recursively determine the first source statistics value (1732), wherein the window size n _a , or the parameter n _i ^k , determines a weight of a most recently decoded binary value of the decoded binary sequence (1722) in determining the first source statistics value or the first state variable value (1732).

The functionality of the first source statistics value determination block (1730) is similar to forming a sliding average with a certain window size, except that a recursive algorithm is used, which introduces some "infinite impulse response" properties, for example. Therefore, the first source statistics value (1732) does not exactly represent the result of a moving window summation operation or a moving window averaging operation, but rather should be considered a "virtual sliding window" operation, since the results are very similar.

Moreover, the second source static value determination block (1740) performs similar operations as compared to the first source statistical value determination block (1730). However, the second source statistical value determination block (1740) typically uses different parameters (e.g., different window length n _b and/or different bit count parameter BITS _b or different parameters n _i ^k ), and consequently, provides a second source statistical value or a second state variable value (1742) that is typically different from the first source statistical value or the first state variable value (1732). For example, one of the source statistical values (1732 , 1742 ) can be a short-term (or shorter-term) average source statistical value, and one of the source statistical values (1732 , 1742 ) can be a long-term (or longer-term) average source statistical value.

It should be noted that the source statistics value determination block (1730, 1740) may perform the same functionality as described for the state variable update portion herein, for example. Furthermore, it should be noted that in some embodiments, different calculation rules may be used in the source statistics value determination block (1730, 1740).

The arithmetic decoder (1720) optionally further includes a combined source statistics value determination block (or unit) (250), which is configured to receive the first source statistics value (1732) and the second source statistics value (1742). The source statistics value combination block (1750) provides the combined source statistics value (1752) based thereon. For example, the source statistics value combination block (1750) can obtain the combined source statistics value (1752) by forming a sum or an average of the first source statistics value (1732) and the second source statistics value (1742).

However, the source statistics value combination block (1750) may apply different weights to the first source statistics value (1732) and the second source statistics value (1742) when deriving the combined source statistics value (1752), wherein the different weights may vary within a slice or between different slices.

For example, the source statistics value combination block (1750) may perform the functionality of the combiner (751) or the combination unit (892). However, it is also possible for this functionality to be changed.

For example, in one (alternative) embodiment, the source statistics value combining block (1750) combines only one of the first statistics values with a fixed value to obtain a combined source statistics value or combined state variable value (1752). This concept can be beneficial to avoid the combined source statistics value (1752) from deviating too much from the expected probability of the binary values within the decoded binary sequence (1722).

The arithmetic decoder (1720) is configured to derive range values (1762) for interval sub-segmentation (which will be provided to the arithmetic decoding core (1770)) based on the combined source statistics or the combined state variable values (1752), or alternatively based on two or more state variable values.

This process step may be considered, for example, "range value determination." For example, the range value determination unit may include an optional value processing unit (1766) that receives the combined source statistics values (1752) and provides a probability value or a state index value based thereon. The value processing unit (1766) may, for example, map the range of values of the combined source statistics values (1752) to a range between 0 and 1, or to a range between 0 and 0.5, or to integer index values.

Optionally, the value processing unit (1766) can provide information (1767), which can be binary information indicating whether the next decoded value (e.g., a decoded value of the decoded binary sequence (1722)) is more likely to take the value "1" or the value "0". Optionally, the arithmetic decoder (or range value determination unit) can include a mapping table (1769). The mapping table (1769) receives, for example, an index value (e.g., pStateIdx) that designates a table entry. Accordingly, the mapping table (1769) can provide one or more range values (1762) corresponding to the table entry designated by the index value (e.g., pStateIdx). Accordingly, by deriving a "state index value" (e.g., pStateIdx) and evaluating a mapping table based on this state index value, one or more range values for an interval subdivision can be provided based on the combined source statistics value (1752).

The mapping table (1769) may have a structure similar to a mapping table described in, for example, Standard H.264 or Standard H.265. Optionally, however, the content of the mapping table may be adapted to specific details of a video decoder. In particular, entries in the mapping table may be adapted to statistical properties expected within a specific video decoder.

However, it should be noted that deriving the interval size information based on one or more state variable values, or based on combined state variable values, may be performed using any of the concepts disclosed herein, for example, using an interval size determination unit as described with reference to any of FIGS. 4 to 15, or using an interval size determination core, or using a state variable update unit.

Additionally, it should be noted that the arithmetic decoding core referred to in this specification may correspond to the arithmetic decoding core disclosed in this specification.

The arithmetic decoder (or, more generally, the video decoder) optionally further comprises a control block (1790) that can receive control information or configuration information and based thereon adjust parameters used to provide range values (and possibly also other parameters, e.g. additional parameters used by the arithmetic decoding core (1770)). For example, the control block (1790) can receive one or more of "cabac init flag", "ws_flag" and "ctu_ws_flag", which are slice type information that can be included in the encoded video information (1710).

Moreover, the control unit (1790) can adjust, for example, the window size parameters n _a , n _b or n _i ^k and/or the bit size parameters BITSa, BITSb depending on the control information. In particular, the control block (1790) can also take into account the current context model. In relation to this issue, it should be noted that it can be determined which context model should be used in order for each bit (or group of bits) of the decoded binary sequence (1722) to be decoded. For example, the determination of which context model to use can be based on the fact that which type of information (decoding parameters, transform coefficients, etc.) is represented by an individual bit (or group of bits). For example, the control block (1790) can be configured to recognize the syntax of the decoded binary sequence (1722) to recognize which syntax element (or which part of the syntax element, e.g., the most significant or least significant bit, or other) should be decoded next. Accordingly, a selection can be made between different context models. It should also be noted that the window size parameter and/or the bit size parameter and/or any other parameter can be selected depending on the context model. Furthermore, it should be noted that the source statistics (1732, 1742) or the combined source statistics (1752) can be associated with a particular context model, such that different source statistics or combined source statistics (or state variable values, or combined state variable values) values can be made available for different context models. For example, source statistics values associated with a particular context model may be optionally provided based on decoded binary values of a decoded binary sequence (1722) that have been decoded using the respective context model. In other words, separate independent processing, and separate (possibly independent) judgments relating to parameters n _a , n _b , n _i ^k , BITS _a , BITS _b , etc. may be performed for different context models.

With respect to the functionality of the control unit (1790), it should be noted that the control unit may determine the parameters n _a , n _b , n _i ^k , BITS _a , BITS _b , for example, according to the mechanisms described below. For example, the window size parameters n _a , n _b , n _i ^k may be selected depending on the slice type information, and/or depending on the cabac init flag, and/or depending on the ws_flag, and/or depending on the ctu_ws_flag. Also, in some embodiments, the bit size parameters BITSa, BITSb may be selected depending on some configuration information. However, in other embodiments, the bit size parameters may be fixed. With respect to mechanisms for adjusting the parameters, see, for example, the discussion below.

Referring now to the video reconstruction block (1780), it should be noted that the video reconstruction block (1780) typically receives the decoded binary sequence (1722) and also at least some elements of the configuration information. For example, the video reconstruction unit (1780) can reconstruct integer parameters and/or floating point parameters and/or image data based on the decoded binary sequence (1722). For example, there may be mapping rules that specify how certain bits or portions of the decoded binary sequence should be mapped to integer parameters or floating point parameters or to image data (e.g., transform coefficients or the like). Accordingly, the video reconstruction block (1780) reconstructs information that is used for reconstructing video frames from the decoded binary sequence (1722). The video reconstruction block can then generate image information based on the reconstructed information (derived from the decoded binary sequence (1722)).

For example, the video restoration unit (1780) may include functionality as described in standard H.264 or standard H.265. However, other approaches may be used for video restoration adapted to provide decoded video content based on the decoded binary sequence (and possibly additional configuration information or control information). Accordingly, the video restoration unit (1780) provides decoded video content (1712), which may take the form of a sequence of video frames.

In conclusion, an overview of a video decoder according to one embodiment of the present invention has been provided. However, it should be noted that different implementations exist for the functional blocks (e.g., implementations exist for the source statistics value determination block (1730, 1740), for the source statistics value combination block (1750), for the value process block (1766), for the mapping table (1769), and for the arithmetic decoding core (1770). Also, different implementations are possible for the video reconstruction block (1780) and the control block (1790).

However, it should also be noted that the functional blocks described in this specification may be supplemented by any of the features, functionality and details disclosed in this application as a whole. It should also be noted that the features, functionality and details disclosed in this application may be introduced individually or in combination to expand the functionality of the video decoder (1700).

18. Additional embodiments

Hereinafter, additional embodiments according to the present invention will be described.

Among other features, functionality and details, a method for updating a context model using a finite state machine will be described, which may be used individually or in combination with any of the features, functionality and details disclosed herein.

introduction

From now on, different and progressive embodiments and aspects will be described, for example, in the chapters “Deriving probability estimates from state variables” and “Updating state variables” and “Preferred embodiments”.

However, features, functionality and details described in any other chapter may also be optionally introduced into embodiments according to the present invention.

Additionally, the embodiments described in the chapters mentioned above may be used individually and may be supplemented by any of the features, functionality and details of other chapters.

It should also be noted that the individual aspects described herein may be used individually or in combination. Thus, details may be added to each of the above aspects without adding details to other of the above aspects.

In particular, the embodiments are also set forth in the claims. The embodiments set forth in the claims may optionally be supplemented by any of the features, functionalities and details described herein, taken individually or in any combination.

It should also be noted that this specification explicitly or implicitly describes features that can be used in a video encoder (a device for providing an encoded representation of an input video signal) and a video decoder (a device for providing a decoded representation of a video signal based on the encoded representation of the video signal). Therefore, any of the features described in this specification can be used in the context of a video encoder and in the context of a video decoder.

Moreover, the features and functionality disclosed in connection with any method in this specification can also be used in a device (a device configured to perform such functionality). Furthermore, any feature and functionality disclosed in connection with any device in this specification can also be used in a corresponding method. In other words, the method disclosed in this specification can be supplemented by any of the features and functionality described with respect to the device.

Additionally, any of the features and functionality described in this specification can be implemented in hardware, in software, or using a combination of hardware and software, as described in the section entitled “Implementation Alternatives.”

Introduction

Context model updating is an important feature of efficient binary arithmetic entropy coders, as it provides the possibility to adapt the coding engine to the underlying source statistics.

In the present invention, each context model is equipped with an independent probability estimation stage which provides a sequence of probability estimates for entropy encoding or decoding, for example, for each symbol of each symbol of the symbols. The basic idea of this context model updating method is to maintain for each context model at least one state variable which together represents the current probability estimate. In order to adapt to the statistics of the symbol sequence, the state variables of the context model are frequently updated (e.g., in a state variable update unit). For example, after encoding of each symbol.

The present invention comprises two important aspects, among several aspects. The first aspect deals with a method for deriving probability estimates (or interval size information) from state variables. The second aspect deals with a method for updating state variables after the appearance of a symbol. These aspects may optionally be used in combination.

The present invention may optionally be combined with a binary arithmetic coding engine, and may also be combined with any other entropy coding engine that requires individual probability estimates for binary symbols to be encoded or decoded. For example, the present invention may also be combined with PIPE coding concepts.

Implementation form details

For example, one or more context models Consider an entropy encoding or decoding application, such as a video compression algorithm employing Almost every binary symbol to be encoded or decoded is clearly associated with one of the context models. In order to encode or decode such a binary symbol, the associated context model provides an entropy coding stage, where probability estimates of binary symbols are is "1". In order to provide good compression efficiency, the portion of the bit stream generated by entropy encoding the binary symbol is "1". It should be close to and in the case of "0" It should be continued.

Each context model In the case of one or more state variables (or state variable values) This is induced is. Each state variable is implemented as a signed integer value, for example, and is a probability value represents the context model Probability estimate of is, for example, the probability value of all state variables in the context model. will be defined as the weighted sum of .

State variables are encouraged to have the following properties, but are not required to:

1. If so, am.

2. The larger the value, the larger the Corresponds to.

3. am.

As a result, the negative state variable is can correspond to. In general, a different function is provided for each state variable of each context model. It is possible to define .

General statement 1

The present invention enables bit-transition operations to be used very efficiently in many cases. Mathematical expression Is is an integer can be implemented by simple bit-shift operations where the power of 2 is . The two complementary representations are When hired, this is It also holds true if is negative.

General statement 2

For example, any variables storing non-integer numbers, such as probability values, weighting factors, lookup table elements, etc., can be implemented in fixed-point or floating-point representations without special care. This introduces rounding operations that may vary for each particular implementation of the present invention.

An example configuration for associating state variables with probability values.

Associating state variables with probability values, i.e., There are many useful ways to implement it. For example, a state representation comparable to the probability estimator of HEVC can be obtained mathematically as follows:

is a weighting factor.

Is is a parameter.

To obtain a structure comparable to HEVC, all and all About and Set up.

These exemplary configurations will give you some insight into how state variables can be defined. In general, It is unnecessary to define it, since it is not used directly, as can be seen in the following. Instead, it is often obtained from the actual implementation of the individual parts of the invention.

Initializing state variables

Before encoding or decoding the first symbol into a context model, all state variables are optionally initialized to identical values that can be optimized for the compression application.

Deriving probability estimates from state variables

For encoding or decoding symbols, probability estimates are derived from the state variables of the context model. Two alternative approaches are presented below. Approach 1 provides more accurate results than Approach 2, but has higher computational complexity.

Approach 1

This approach consists of two steps: first, each state variable of the context model is the probability value is converted to . Second, the probability estimate is the probability value is derived as a weighted sum of .

Step 1:

State variables , for example, the corresponding probability value according to mathematical expression 1 Lookup table LUT1 is employed to convert to .

is a lookup table containing probability values.

Is cast is a weighting factor that adapts to the size of the image.

These steps may be performed, for example, by blocks (882 and 884).

Step 2:

Probability Estimate A, for example, the probability value according to the following is derived from:

[Mathematical formula 7]

is a weighting factor that controls the influence of individual state variables.

This step may be performed, for example, by block (886).

Approach 2

An alternative approach to deriving probability estimates from state variables is presented below. It provides less accurate results and has lower computational complexity. First, the weighted sum of state variables is derived, for example, as follows:

is a weighting factor that controls the influence of each state variable.

This step may be performed, for example, by block (892).

Second, the probability estimate is a state variable From the weighted sum of , it is derived, for example, as follows:

is a lookup table containing probability estimates.

Is cast is a weighting factor that adapts to the size of the image.

This step may be performed, for example, by block (894).

Optional changes to Approaches 1 and 2

For software implementation, throughput can be increased if as many operations as possible can be transitioned into the lookup table. This becomes easier for Approach 1 if Equation 1 is replaced by:

For Approach 2, Equation 2 is replaced by:

In both mathematical expressions, this change allows the case differentiation to be incorporated into the lookup table, which requires only twice as many elements as before. However, for achieving high throughput, reducing the number of operations may be helpful, but the increase in the lookup table size may be less relevant.

Without further caveats, approaches 1 and 2 can be selectively applied to all applications of approaches 1 and 2 of the present invention.

Combination with the binary arithmetic coding engine of CABAC (M coder) (optional)

CABAC's M-coder employs a 2D lookup table to replace the odds required to subdivide coding intervals. is called the coding interval prior to the arithmetic encoding of binary symbols. Silver, for example, interval can be in. The symbol to be encoded is a probability estimate for binary arithmetic encoding or decoding. Context model used to derive is associated with two subintervals and The width of each needs to be derived. For example, CABAC's M coder (which serves as an example) avoids this odds by employing a 2D lookup table. Probability estimates Recall that the symbol is the estimated probability of 1 day. However, the M coder uses the probability of the less likely of both symbols 0 and 1 to determine the width of the subinterval. Then, the most likely symbol is The subinterval width of From can be easily derived by subtracting .

Note that, depending on the implementation of the M coder, it may not fall below a predefined minimum allowable value. For example, this minimum allowable value may be 2, 3, or 4. In the remainder of this specification, Before passing it to the M-coder, it is assumed that it is repeatedly increased by 1 (if it is increased) until it is at least as large as a predefined smallest allowed value. This corresponds to a clipping operation and can be implemented as a separate computational step. It may be possible to directly incorporate this into some of the approaches presented in the following (e.g., by adjusting a lookup table value).

Less likely symbol The probability of is given by

.

For example, a lookup table can have 8x32 or 8x16 elements, The allowable values for are quantized into 8 cells, is quantized into 32 or 16 cells. Then,

.

and Is and Here is a quantization function for each.

Alternative 1:

Alternatively, the lookup table (probTabLPS) has 32 or 16 elements, with the allowed values for R quantized into 8 or 16 cells. is quantized into 32 or 16 cells. Then,

and Is and Here is a quantization function for each.

In general, it is desirable that both quantization functions be easily implemented. Any quantization function can be used as long as its elements are appropriately chosen.

This can be utilized for the present invention.

Lookup table to derive probability estimates for context models or Recall that it was necessary to employ these lookup tables. can be integrated into (or, more generally, integrated into the lookup-table of the M-coder and into another two-dimensional lookup-table).

Instead of computing probability estimates in approaches 1 and 2, the subinterval widths are For given values of , it is computed directly, for example, as follows:

For approach 1, is multiplied on both sides of Equation 1 and Equation 7 to obtain the following

Next, These different quantized values Pre-calculated product for the desired number of is replaced by a 2D lookup table containing (an example of an actual implementation of the implementation form).

The resulting 2D lookup-table can be used, for example, in blocks (736 and 738).

For approach 2, is multiplied on both sides of Equation 2, resulting in the following

Next, Different quantized values Pre-calculated product for the desired number of is replaced by a 2D lookup table containing (an example of an actual implementation form of the embodiment). If this becomes a 2D lookup table, then Equation 8 becomes

As can be seen from mathematical expression 9, , within a single lookup table, for example: and Includes.

LUT3 or equation 9 can be used, for example, in block (756).

Alternatively, LUT3 can be replaced with LUT4 (1D) and a multiplication operation according to the technique presented as Alternative 1.

Function can be defined, for example, as follows:

Here , and Depends on the compression application.

for example, , , and am.

Then, the context model For the arithmetic encoding of binary symbols associated with , the subinterval width To derive, only the state variables Simply derive the weighted sum according to Equation 10 and execute Equation 9.

The same argument holds for Approach 1.

From now on, An additional (optional, alternative) way to efficiently implement (or derive interval size information) is provided. Instead of storing the entire lookup table, elements are computed on the fly as needed. For this purpose, a new lookup table will be defined. This is done by employing simple operations. Contains values that can be used to derive each element of .

In general, for example, RangeTabLPS[i][j] can be evaluated in block (870), where an entry of RangeTabLPS can be obtained (either before or immediately) using, for example, BaseTabLPS and a corresponding scaling function Scal(x, y) (an embodiment using BaseTabLPS), or using ProbTabLPS and a corresponding scaling function Scal(x, y) (an embodiment using ProbTabLPS).

In a preferred embodiment (e.g. one using BaseTabLPS), is the size It will be, and the size person As follows will be generated from:

is a scaling function. For example, , , , And,

{

{ 125, 140, 156, 171, 187, 203, 218, 234, },

{ 108, 121, 135, 148, 162, 175, 189, 202, },

{ 94, 105, 117, 129, 141, 152, 164, 176, },

{ 81, 91, 101, 111, 121, 131, 141, 151, },

{ 71, 79, 88, 97, 106, 115, 124, 133, },

{ 61, 68, 76, 83, 91, 99, 106, 114, },

{ 53, 59, 66, 72, 79, 86, 92, 99, },

{ 46, 51, 57, 63, 69, 74, 80, 86, },

{ 40, 45, 50, 55, 60, 65, 70, 75, },

{ 35, 39, 43, 48, 52, 56, 61, 65, },

{ 31, 34, 38, 42, 46, 50, 54, 58, },

{ 27, 30, 33, 37, 40, 43, 47, 50, },

{ 24, 27, 30, 33, 36, 39, 42, 45, },

{ 21, 23, 26, 28, 31, 34, 36, 39, },

{ 18, 20, 22, 24, 27, 29, 31, 33, },

{ 16, 18, 20, 22, 24, 26, 28, 30, },

} is. (Example)

In other words, for example, The upper half of the floor operation is applied to each element. consists of (or includes) the values of . For example, The lower half of the array is divided by 8 (or some other number) for each element, and (optionally) a floor operation is performed. consists of (or contains) values of , which correspond to a right-transition of, for example, 3.

This approach lesser You just need to save it, It exploits the fact that the values in a row of a function decay exponentially as the row increases, for example. Exponential decay is a parameter It depends.

In another example (e.g. another embodiment using BaseTabLPS), , , , And,

{

{ 121, 136, 151, 166, 181, 196, 211, 226, },

{ 100, 112, 125, 137, 150, 162, 175, 187, },

{ 83, 93, 103, 114, 124, 134, 145, 155, },

{ 70, 78, 87, 96, 105, 113, 122, 131, }

} is. (Example)

This configuration is, The values in the rows of each of the four rows are divided into two equal parts. Can be used when selected. The value of is, for example, associated Note that it can be extracted from .

The approach involving may be (optionally) combined with Alternative 1 and the associated preferred embodiment as defined in Equation 11. Alternative 1 is can be considered as an approach to derive a row from a single constant and a computational operation (for each row). A, for example Since it includes scaled rows (ignoring rounding), Alternative 1 is can be applied to induce.

In a preferred embodiment (e.g., in another embodiment using ProbTabLPS), the size person is defined. The size is person For example, as follows: can be generated from:

for example, , , , , , And,

{

125,

108,

94,

81,

71,

61,

53,

46,

40,

35,

31,

27,

24,

21,

18,

16,

} is. (Example)

then According to the approach described above can be calculated from . Each value of, for example, After calculating the associated values, the scaling function Note that this can be quickly computed by applying:

This approach only See, and therefore lesser You just need to save it.

According to the same argument, One column of, for example, simply and By ignoring all other columns can be used to derive only one column. The induced heat is now, for example, by adopting Alternative 1 according to Equation 11. can be used to derive the remaining heat.

In a preferred embodiment, the size is person is defined. The size is person is as follows can be generated from:

Note that (eg)

of state variables Update (Aspect of the present invention)

After encoding or decoding a symbol, one or more state variables of the context model may be updated to track the statistical behavior of the symbol sequence. This may be done, for example, at block (640).

Updates are performed, for example, as follows:

is a lookup table that stores integer values.

and is a weighting factor that controls the 'agility' of the update.

is a lookup table An offset that ensures that it is accessed only with non-negative values.

As described below, the lookup table The value of my underwear can be chosen to stay within a given specific interval.

Alternatively, it is possible to introduce a clipping operation, for example the following, which is performed after each execution of equation (3):

Is is the maximum allowable value for

Is is the minimum allowable value for

In order to optimize the lookup table A for compression applications, the assumed function approximated by the values of the lookup table A can also be replaced by a single computational operation. For example, the following holds true.

Here , , and is a parameter that controls the probability update behavior.

Note that this way of generating the lookup table A does not involve clipping operations as described above. Now, in Equation 7, Evaluate the compression efficiency for different combinations of and subsequently obtain the desired value. at Lookup table A can be optimized by subsequent sampling.

A particular encoder or decoder application chooses whether to use a computational operation or an equivalence table (a table containing values derived via a computational operation).

To optimize the lookup table A for the video compression context, the following range of possible configurations are used:

Optional changes to equation 3

To achieve higher throughput in an optimized software implementation, two optional modifications can be made to Equation 3.

For the first optional change example, Equation 3 is replaced by:

[Mathematical expression 3a]

For the second optional change example, Equation 3 is replaced by:

[Mathematical expression 3b]

For a combination of the first and second optional modifications, Equation 3 is replaced by:

[Mathematical expression 3c]

By employing a combination of the first and second optional modifications, it is possible to integrate case differentiation into the lookup table A , which requires only twice as many elements as before. However, for achieving high throughput, reducing the number of operations may be helpful, but increasing the lookup table size may be less relevant.

Without further ado, the two optional modifications can be applied (either individually or in combination) to all applications of Equation 3 of the present invention.

Preferred embodiment (details are optional)

In a preferred embodiment, the following configuration is used:

The number of context models M depends on the compression application.

Approach 2 is used to derive probability estimates from state variables.

Mathematical expression 3 is used to update the state variables.

Optional clipping according to Equation 6 is not used.

Before encoding the symbol, Go interval will be initialized with values from , is the interval will be initialized with values from .

For this configuration, mathematical expression 3 can be written as:

Go interval If it is within, Equation 4 remains within the same interval regardless of the value of the symbol to be encoded. Produces updated values for .

Go interval If it is within, Equation 5 remains within the same interval regardless of the value of the symbol to be encoded. Produces updated values for .

As a result, can be implemented as an 8-bit signed integer value, for example, can be implemented as a 12-bit signed integer.

Both equations increase the state variable (up to some maximum value) after encoding 1 and decrease the state variable (up to some minimum value) after encoding 0. However, equation 4 is By a value greater than the amount that increases or decreases tends to increase or decrease. In other words, While it adapts more quickly to previously encoded symbols, adapts more slowly.

In another preferred embodiment, the same configuration as for the previous preferred embodiment is used, but the first and second optional modifications are applied to Equation 3 to yield:

Note that lookup tables LUT2 and A are typically optimized for specific compression applications.

When lookup table A is optimized, the following configuration is used with Equation 7:

then

This is it.

Note that A is already clipped, because its last value is 0 instead of 4.

In another preferred embodiment, the configuration is identical to the previous preferred embodiment except that:

Clipping according to Equation 6 is used after executing Equation 3 with the following parameters:

The lookup table contains the following values:

Note that only the last element A in the above lookup table has changed, and now all values in the second half of A have the value 4, which can be implemented efficiently.

Imagine that the lookup table is truncated after the first four digits and the access index for the table is clipped to the last table element (optional change in implementation).

This trick can be selectively employed for different versions of lookup table A , as long as the number of elements at the end of the table has the same value.

In another preferred embodiment, the configuration is identical to the previous preferred embodiment except that:

Alternative 1 with size 32 is used.

In another preferred embodiment, the configuration is identical to the previous preferred embodiment.

In another preferred embodiment, the configuration is identical to the previous preferred embodiment except that:

Alternative 1 with size 16 is used.

In another preferred embodiment, the configuration is identical to the previous preferred embodiment.

In another preferred embodiment, the following configuration is used:

The number of context models M depends on the compression application.

Approach 2 is used to derive probability estimates from state variables.

Mathematical expression 3 is used to update the state variables.

Optional clipping according to Equation 6 is not used.

Before encoding the symbol, Go interval will be optionally initialized with values from .

In another preferred embodiment, approach 2 is used, and parameters are adjusted to obtain different probabilistic update behaviors for different context models. , , and is set differently for different context models.

In another preferred embodiment, approach 1 is used and parameter , , and is set differently for different context models. In another preferred embodiment, when approach 1 or approach 2 is used, N = 1, and to obtain different probability update behaviors for different context models, the parameter , , and is set differently for different context models.

When lookup table A is optimized, the following configuration is used with Equation 7:

then

This is it.

Note that A is already clipped, because its last value is 0 instead of 4.

In another preferred embodiment, when approach 1 or approach 2 is used, N = 2, and to obtain different probabilistic update behaviors for different context models, the parameter , , and is set differently for different context models.

When lookup table A is optimized, the following configuration is used with Equation 7:

then

This is it.

Alternatively, This is also a desirable configuration in this embodiment, which results in the following:

Note that A is already clipped, because its last value is 0 instead of 4.

19. Implementation alternatives:

Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of a corresponding method, wherein a block or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method also represent a description of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be implemented by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer or an electronic circuit. In some embodiments, one or more of the most significant method steps may be implemented by such a device.

Depending on the requirements of a particular implementation, embodiments of the present invention may be implemented in hardware or software. The implementation may be performed using a digital storage medium having stored thereon electronically readable control signals, such as a floppy disk, DVD, Blu-ray, CD, ROM, PROM, EPROM, EEPROM or FLASH memory, which interacts (or can interact) with a computer system programmable to perform each method. Thus, the digital storage medium is computer-readable.

Some embodiments according to the present invention include a data carrier having electronically readable control signals that can interact with a programmable computer system to cause one of the methods described herein to be performed.

In general, embodiments of the present invention may be implemented as a computer program product having program code, the program code being operable to perform one of the methods when the computer program product is executed on a computer. The program code may be stored, for example, on a machine-readable carrier.

Other embodiments include a computer program stored on a machine-readable carrier to perform one of the methods described herein.

In other words, therefore, one embodiment of the method of the present invention is a computer program having program code for performing one of the methods described herein when the computer program is executed on a computer.

Therefore, another embodiment of the method of the present invention is a data carrier (or digital storage medium, or computer-readable medium) having recorded thereon a computer program for performing one of the methods described herein. A data carrier, digital storage medium or recording medium is typically not tangible and/or transitory.

Therefore, another embodiment of the method of the present invention is a data stream or sequence of signals representing a computer program for performing one of the methods described herein. The data stream or sequence of signals may be configured to be transmitted, for example, over a data communications connection, for example, over the Internet.

Another embodiment comprises a processing means, for example a computer or a programmable logic device, configured or adapted to perform one of the methods described herein.

Another embodiment comprises a computer having installed thereon a computer program for performing one of the methods described herein.

Additional embodiments according to the present invention include a device or system configured to transmit (e.g., electronically or optically) a computer program for performing one of the methods described herein to a receiver. The receiver may be, for example, a computer, a mobile device, a memory device, or the like. Such a device or system may include, for example, a file server for transmitting the computer program to the receiver.

In some embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, the field programmable gate array may interact with a microprocessor to perform one of the methods described herein. In general, such methods are preferably performed by any hardware device.

The devices described in this specification can be implemented using hardware devices, using a computer, or using a combination of hardware devices and a computer.

The devices described herein, or any components of the devices described herein, may be implemented at least partially in hardware and/or software.

The method described herein can be performed using a hardware device, or using a computer, or using a combination of a hardware device and a computer.

Any of the methods described herein, or any of the components of the devices described herein, may be performed at least in part by hardware and/or by software.

The embodiments described herein are merely illustrative of the principles of the present invention. It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. Therefore, it is not intended to be limited by the scope of the pending claims and by the specific details presented by describing and explaining the embodiments herein.

Claims (235)

An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
Based on a plurality of state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously encoded symbol values having different adaptation time constants, it is configured to derive interval size information (432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic encoding of one or more symbol values to be encoded,
The above arithmetic encoder obtains interval size information describing an interval size for arithmetic encoding of one or more symbols to be encoded.
Mapping the first state variable value, or a scaled version and/or a rounded version of the first state variable value, using a lookup table (LUT1),
An arithmetic encoder configured to map a second state variable value, or a scaled version and/or a rounded version of said second state variable value, using said lookup table (LUT1). In paragraph 1,
The above arithmetic encoder is,
configured to map the first state variable value, or a scaled version and/or a rounded version of the first state variable value, to a first probability value using the lookup table,
The above arithmetic encoder is,
configured to map the second state variable value, or a scaled version and/or a rounded version of the second state variable value, to a second probability value using the lookup table,
An arithmetic encoder, wherein the arithmetic encoder is configured to obtain a combined probability value using the first probability value and the second probability value. In the second paragraph,
The above arithmetic encoder is,
If the symbol to be encoded has a first value, the state variable value is changed in the first direction, and if the symbol to be encoded has a second value different from the first value, the state variable value is changed in the second direction.
An arithmetic encoder, wherein the arithmetic encoder is configured to determine which entry of a lookup table is to be evaluated based on the absolute value of an individual state variable value. In the third paragraph,
The above arithmetic encoder is,
If the first state variable value has the first sign, the first probability value is configured to be set to a value provided by the lookup table,
The above arithmetic encoder is,
An arithmetic encoder configured to set the first probability value (p ^k ₁ ) to a value obtained by subtracting a value provided by the lookup table from a predetermined value if the first state variable value has a second sign. In the second paragraph,
The above arithmetic encoder is,
Two or more probability values p ^k _i

It is configured to decide accordingly,
LUT1 is a lookup table containing probability values,
. is the floor operator,
s ^k _i is the i-th state variable value,
An arithmetic encoder, where a ^k _i is a weighting value associated with the i-th state variable value. In the second paragraph,
The above arithmetic encoder is,
Two or more probability values p ^k _i

It is configured to decide accordingly,
LUT1 is a lookup table containing probability values;
. is the floor operator,
s ^k _i is the i-th state variable value,
An arithmetic encoder, where a ^k _i is a weighting value associated with the i-th state variable value. In the second paragraph,
The above arithmetic encoder is,

Accordingly, it is configured to obtain the combined probability value p ^k based on a plurality of probability values p ^k _i ,
N is the number of probability values considered,
arithmetic encoder, where b ^k _i are weights. In paragraph 1,
The above arithmetic encoder is,
configured to map the first state variable value, or a scaled version and/or a rounded version of the first state variable value, to a first subinterval width value using a two-dimensional lookup table whose entries are addressed depending on the first state variable value and depending on coding interval size information describing the size of a coding interval of an arithmetic encoding prior to encoding of a symbol;
The above arithmetic encoder is,
configured to map said second state variable value, or a scaled version and/or a rounded version of said second state variable value, to a second subinterval width value using a two-dimensional lookup table whose entries are addressed depending on said second state variable value and depending on coding interval size information describing the size of a coding interval of an arithmetic encoding prior to encoding of a symbol;
The above arithmetic encoder is,
An arithmetic encoder configured to obtain a combined sub-interval width value using the first sub-interval width value and the second sub-interval width value. In Article 8,
The above two-dimensional lookup table is,
a first 1-dimensional vector entry comprising probability values for different value intervals of the value domain for the first state variable value and the second state variable value, or for scaled versions and/or rounded versions of the first state variable value and the second state variable value, and
An arithmetic encoder which can be expressed as a dyadic product between second 1-dimensional vector entries including quantization levels for the above coding interval size information. In Article 8,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the base lookup table (Base TabLPS).
A first group of elements of the above two-dimensional lookup table are identical to elements of the above base lookup table or are rounded versions of elements of the above base lookup table,
An arithmetic encoder, wherein the second group of elements of the two-dimensional lookup table are scaled and rounded versions of the elements of the base lookup table. In Article 10,
An arithmetic encoder, wherein the second group of elements of the two-dimensional lookup table are right-shifted versions of the elements of the base lookup table. In Article 10,
A probability index based on one of the above state variable values determines whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated,
The first range of probability indices is associated with the elements of the first group of elements,
An arithmetic encoder, wherein the second range of the above probability indices is associated with elements of a second group of elements. In Article 12,
An arithmetic encoder, wherein a division residual of a division between a first size value and a probability index, which describes an extension of a base lookup table in a first direction, and an interval size index, which is obtained based on coding interval size information, determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table. In Article 9,
The above arithmetic encoder is,
It is configured to obtain elements of the above two-dimensional lookup table as follows:
RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j], i/μ )
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In Article 8,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the probability table (probTabLPS),
The above probability table describes the interval size for a set of multiple probability values associated with table indices and for a given coding interval size,
An arithmetic encoder, wherein elements of a two-dimensional lookup table for probability values not included in the set of the plurality of probability values or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling. In Article 15,
The elements of the above two-dimensional lookup table are:
- Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
- Using a second scaling of the result of the first scaling, depending on whether the element associated with the current probability value is included in the set of said probability values,
Obtained, arithmetic encoder. In Article 16,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
An integer division result of the division between said probability index and said first magnitude value, which represents a current probability value, determines a scaling factor used in said second scaling, and/or
An arithmetic encoder, wherein the above coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In Article 15,
The above arithmetic encoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In Article 15,
The elements of the above two-dimensional lookup table are:
An arithmetic encoder obtained by using a first scaling of a selected element of the probability table, depending on whether the element associated with the current probability value is included in the set of probability values, and a second scaling of the result of the first scaling, depending on the coding interval size (R). In Article 19,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between said probability index and said first magnitude value, which represents the current probability value, determines the scaling factor used in said first scaling, and/or
An arithmetic encoder in which the above coding interval size (R) determines the multiplication scaling factor (Qr ₂ (R)) of the second scaling. In Article 15,
The above arithmetic encoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In Article 8,
The above two-dimensional lookup table is,
a first 1-dimensional vector entry comprising probability values for different value intervals of the value domain for the first state variable value and the second state variable value, or for scaled versions and/or rounded versions of the first state variable value and the second state variable value, and
An arithmetic encoder which can be expressed as a dyadic product between second 1-dimensional vector entries including quantization levels for the above coding interval size information. In paragraph 1,
The above arithmetic encoder is,
From the first state variable value and the second state variable value, or the scaled version and/or the rounded version of the first state variable value and the second state variable value, first and second subinterval width values (R*p ^k ),
Mapping the first and second state variable values, or the scaled and/or rounded versions of the first and second state variable values, to the first and second probability values using a one-dimensional lookup table (LUT4) entry containing probability values for different value intervals of the value domain for the first state variable value and the second state variable value, or the scaled and/or rounded versions of the first state variable value and the second state variable value,
The coding interval size information describing the size of the coding interval of the above arithmetic encoding prior to encoding of the symbol is quantized into a quantization level.
In one aspect, the product of the first and second probability values and the quantization level is determined,
An arithmetic encoder configured to calculate, respectively, a combined sub-interval width value by using the first sub-interval width value and the second sub-interval width value. In paragraph 23,
The above arithmetic encoder is,
An arithmetic encoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In paragraph 23,
The above arithmetic encoder is,
Quantizing the coding interval size information R is configured to perform by,
Here , and is an arithmetic encoder with integer-valued parameters. In Article 24,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases as the first state variable value and the second state variable value, or scaled versions and/or rounded versions of the first state variable value and the second state variable value increase. In paragraph 23,
An arithmetic encoder wherein different value intervals of the value domain for the first state variable value and the second state variable value, or for scaled versions and/or rounded versions of the first state variable value and the second state variable value, are sized identically. In Article 27,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases at a decreasing rate as the first state variable value and the second state variable value, or the scaled version and/or rounded version of the first state variable value and the second state variable value, increases. An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
Based on a plurality of state variable values (s _i ^k ; 642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously encoded symbol values having different adaptation time constants, it is configured to derive interval size information (432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic encoding of one or more symbol values to be encoded,
The above arithmetic encoder is,
Based on the above multiple state variable values, it is configured to derive a combined state variable value (751a; 893; 1132),
The above arithmetic encoder obtains interval size information describing an interval size for the arithmetic encoding of one or more symbols to be encoded.
An arithmetic encoder configured to map combined state variable values, or scaled versions and/or rounded versions (753;) of said combined state variable values, using a lookup table. In Article 29,
The above arithmetic encoder is,
An arithmetic encoder configured to determine a weighted sum of state variable values to obtain the combined state variable values. In Article 29,
The above arithmetic encoder is,
In order to obtain the above combined state variable values,
An arithmetic encoder configured to determine a sum of rounded values obtained by rounding a product of state variable values and weight values associated with the state variable values. In Article 29,
The above arithmetic encoder is,
The above combined state variable values s _k

It is configured to decide accordingly,
Here, s ^k _i is the state variable value,
N is the number of state variable values considered,
. is the floor operator,
d ^k _i is an arithmetic encoder, which is a weight value associated with the state variable value. In Article 29,
The above arithmetic encoder is,
If the symbol to be encoded has a first value, the state variable value is changed in the first direction, and if the symbol to be encoded has a second value different from the first value, the state variable value is changed in the second direction.
An arithmetic encoder, wherein the arithmetic encoder is configured to determine an entry of a lookup table to be evaluated based on the absolute value of the combined state variable values. In paragraph 33,
The above arithmetic encoder is,
If the above combined state variable value has a first sign, the probability value describing the symbol probability is set to a value provided by the lookup table,
The above arithmetic encoder is,
An arithmetic encoder configured to set the probability value to a value obtained by subtracting a value provided by the lookup table from a predetermined value if the combined state variable value has a second sign. In Article 29,
The above arithmetic encoder is,
The combined probability value p _k , which describes the symbol probability,

It is configured to decide accordingly,
Here, LUT2 is a lookup table containing probability values,
. is the floor operator,
s _k is the combined state variable value,
a _k is an arithmetic encoder, which is a weight associated with the combined state variable values. In Article 29,
The above arithmetic encoder is,
A combined probability value p _k that describes the symbol probability

It is configured to decide accordingly,
Here, LUT2 is a lookup table containing probability values,
. is the floor operator,
s _k is the combined state variable value,
a _k is an arithmetic encoder, which is a weight associated with the combined state variable values. In Article 29,
The above arithmetic encoder is,
Subinterval width cast

It is configured to decide accordingly,
Here LUT3 is a 2D lookup table,
. is the floor operator,
s ^k is the combined state variable value,
a ^k is the weight associated with the above combined state variable values,
R is the interval size,
An arithmetic encoder, which is a quantized value of interval size. In Article 29,
The above arithmetic encoder is,
An arithmetic encoder configured to map the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, to subinterval width values using a two-dimensional lookup table, the entries of which depend on the combined state variable values and are addressed depending on coding interval size information describing the size of a coding interval of the arithmetic encoding prior to encoding of a symbol. In paragraph 38,
The above two-dimensional lookup table is,
a first 1-dimensional vector entry comprising probability values for different value intervals of the value domain for the combined state variable values, or for scaled and/or rounded versions of the combined state variable values, and
An arithmetic encoder which can be expressed as a dyadic product between second 1-dimensional vector entries including quantization levels for the above coding interval size information. In paragraph 38,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the base lookup table (Base TabLPS),
A first group of elements of the above two-dimensional lookup table are identical to elements of the above base lookup table or are rounded versions of elements of the above base lookup table,
An arithmetic encoder, wherein the second group of elements of the two-dimensional lookup table are scaled and rounded versions of the elements of the base lookup table. In Article 40,
An arithmetic encoder, wherein the second group of elements of the two-dimensional lookup table are right-shifted versions of the elements of the base lookup table. In Article 40,
A probability index, derived directly from the combined state variable values or using a combined probability value based on the combined state variable values, determines whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated,
The first range of probability indices is associated with the elements of the first group of elements,
An arithmetic encoder, wherein the second range of the above probability indices is associated with elements of a second group of elements. In paragraph 42,
An arithmetic encoder, wherein a division residual of a division between a first size value and a probability index, which describes an extension of a base lookup table in a first direction, and an interval size index, which is obtained based on coding interval size information, determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table. In paragraph 39,
The above arithmetic encoder is,
It is configured to obtain elements of a two-dimensional lookup table (RangeTabLPS) as follows:
RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j], i/μ ),
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In paragraph 38,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the probability table (probTabLPS),
The above probability table describes the interval size for a set of multiple probability values associated with table indices and for a given coding interval size,
An arithmetic encoder, wherein elements of a two-dimensional lookup table for probability values not included in the set of the plurality of probability values or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling. In paragraph 45,
The elements of the above two-dimensional lookup table are:
Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
An arithmetic encoder obtained by using a second scaling of the result of said first scaling, depending on whether the element associated with the current probability value is included in the set of said probability values. In paragraph 46,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
An integer division result of the division between said probability index and said first magnitude value, which represents a current probability value, determines a scaling factor used in said second scaling, and/or
An arithmetic encoder, wherein the above coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In paragraph 45,
The above arithmetic encoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In paragraph 45,
The elements of the above two-dimensional lookup table are:
An arithmetic encoder obtained by using a first scaling of a selected element of the probability table, depending on whether the element associated with the current probability value is included in the set of probability values, and a second scaling of the result of the first scaling, depending on the coding interval size (R). In paragraph 49,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table, determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the first scaling, and/or
An arithmetic encoder in which the above coding interval size (R) determines the multiplication scaling factor (Qr ₂ (R)) of the second scaling. In paragraph 45,
The above arithmetic encoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In Article 29,
The above arithmetic encoder is,
From the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, a subinterval width value,
Mapping the combined state variable value, or a scaled version and/or a rounded version of the combined state variable value, to a combined probability value using a one-dimensional lookup table (LUT4) entry containing probability values for different value intervals of the value domain for the combined state variable value, or the scaled version and/or the rounded version of the combined state variable value,
The coding interval size information describing the size of the coding interval of the above arithmetic encoding prior to encoding of the symbol is quantized into a quantization level.
An arithmetic encoder configured to compute by determining a product of the combined probability value and the quantization level. In paragraph 52,
The above arithmetic encoder is,
An arithmetic encoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In paragraph 52,
The above arithmetic encoder is,
Quantizing the coding interval size information R is configured to perform by,
Here , and is an arithmetic encoder with integer-valued parameters. In paragraph 52,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. In paragraph 52,
An arithmetic encoder wherein different value intervals of the value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, are sized identically. In paragraph 56,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases at a decreasing rate as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. In Article 29,
The above lookup table is an arithmetic encoder that specifies exponential decay. In Article 29,
The above arithmetic encoder is,
Multiple variable state values cast

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
Updated To avoid going beyond the predetermined value range, or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being encoded is 1 And,
If the symbol being encoded is 0 In, arithmetic encoder. In paragraph 59,
The above arithmetic encoder is,
By table lookup or calculation An arithmetic encoder configured to induce . In Article 29,
The above arithmetic encoder is,
Multiple variable state values cast

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
In, arithmetic encoder. An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
configured to determine one or more state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously encoded symbol values,
The above arithmetic encoder is,
It is configured to derive interval size information (432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values representing statistics of a plurality of previously encoded symbol values,
The above arithmetic encoder is,
An arithmetic encoder configured to update the value of a first state variable depending on the symbol to be encoded and using a lookup table. In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to update a second state variable value (s ^k ₂ ) depending on the symbol to be encoded and using a lookup table (A). In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to update the first state variable value and the second state variable value using different adaptation time constants. In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to selectively increment or decrement a previous state variable value by a value determined using the lookup table, depending on whether a symbol to be encoded has a first value or a second value different from the first value. In paragraph 62,
The above arithmetic encoder is,
If the symbol to be encoded has a first value, the previous state variable value is configured to be increased by a relatively larger value when the previous state variable value is negative compared to when the previous state variable value is positive,
The above arithmetic encoder is,
An arithmetic encoder configured to decrease the previous state variable value by a relatively larger value when the previous state variable value is positive compared to when the previous state variable value is negative, if the symbol to be encoded has a second value different from the first value. In paragraph 62,
The above arithmetic encoder is,
If the symbol to be encoded has a first value, the index of an entry of the lookup table to be evaluated when updating the first state variable value is determined based on a sum of a predetermined offset value (z) and a previously computed first state variable value, or a scaled version and/or a rounded version of the previously computed first state variable value,
The above arithmetic encoder is,
An arithmetic encoder configured to determine an index of an entry of the lookup table to be evaluated when updating the first state variable value, depending on a sum of a predetermined offset value (z) and an inverted version of the previously computed first state variable value, or a scaled version and/or a rounded version of the inverted version of the previously computed first state variable value, if the symbol to be encoded has a second value. In paragraph 62,
The above arithmetic encoder is,
If the symbol to be encoded has a first value, the index of an entry of the lookup table to be evaluated when updating the second state variable value is determined based on a sum of a predetermined offset value (z) and a previously computed second state variable value, or a scaled version and/or a rounded version of the previously computed second state variable value,
The above arithmetic encoder is,
An arithmetic encoder configured to determine an index of an entry of the lookup table to be evaluated when updating the second state variable value, depending on a sum of a predetermined offset value (z) and an inverted version of the previously computed second state variable value, or a scaled version and/or a rounded version of the inverted version of the previously computed second state variable value, if the symbol to be encoded has a second value. In paragraph 62,
The above arithmetic encoder is,
When determining an index of an entry of the lookup table to be evaluated when updating the first state variable value, a first scaling value is configured to be applied to scale the previously calculated first state variable value,
The arithmetic encoder is configured to apply a second scaling value to scale a previously computed second state variable value when determining an index of an entry of the lookup table to be evaluated when updating a second state variable value,
An arithmetic encoder wherein the first scaling value is different from the second scaling value. In paragraph 62,
The above arithmetic encoder is,
When updating the first state variable value, the value returned by the evaluation of the lookup table is configured to be scaled using the first scaling value,
The above arithmetic encoder is,
When updating the value of the second state variable, the value returned by the evaluation of the lookup table is configured to be scaled using the second scaling value,
An arithmetic encoder wherein the first scaling value is different from the second scaling value. In paragraph 62,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In paragraph 62,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In paragraph 62,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In paragraph 62,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In paragraph 71,
An arithmetic encoder in which the entries of A monotonically decrease as the lookup table index increases. In paragraph 71,
A is
Updated To avoid going beyond the predetermined value range,
or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being encoded is 1 And,
If the symbol being encoded is 0 In, arithmetic encoder. In paragraph 62,
The last entry in the above lookup table is an arithmetic encoder, which is equal to zero. In paragraph 71,
A is
In, arithmetic encoder. In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to apply a clipping operation to the updated state variable values so as to keep the updated state variable values and the clipped state variable values within a predetermined range of values. In paragraph 79,
The above arithmetic encoder is,
Clipping operation

is configured to apply to the updated state variable values according to
Here Is is the maximum allowable value for ,
Is The minimum allowable value for an arithmetic encoder. In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to apply different scaling values for different context models. In paragraph 62,
The above arithmetic encoder is,
An arithmetic encoder configured to obtain interval size information as specified in paragraph 1. An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
It is configured to derive interval size values (R _LPS ; 432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values (s _i ^k ; 642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously encoded symbol values,
The above arithmetic encoder is,
It is configured to determine the interval size value (R _LPS ) using the base lookup table (Base TabLPS).
The above arithmetic encoder is,
The interval size value (R LPS) is determined such that if the probability index (i; 852; 1332; 1432; 1532) obtained based on the one or more state variable values is within a first range, the determined interval size value is equal to an element of the base lookup table or a rounded version of an element of the base lookup table, and if the probability index is within a _second range, the determined interval size value is obtained using scaling and rounding of the elements of the base lookup table.
The above arithmetic encoder is,
An arithmetic encoder configured to perform arithmetic encoding of one or more symbols using said interval size values (R _LPS ). In paragraph 83,
The above arithmetic encoder is,
An arithmetic encoder configured to determine the interval size value (R _LPS ) such that the determined interval size value becomes a right-shifted version of an element of the base lookup table if the above probability index is within the second range. In paragraph 83,
The above probability index is,
An arithmetic encoder that determines whether an element of the base lookup table is provided as the interval size value (R _LPS ), or whether an element of the base lookup table is scaled and rounded to obtain the interval size value (R _LPS ). In paragraph 83,
An arithmetic encoder, wherein a division residual of a division between a first size value and a probability index, which describes an extension of a base lookup table in a first direction, and an interval size index, which is obtained based on coding interval size information, determines which element of the base lookup table is used to obtain the interval size value. In paragraph 83,
The above arithmetic encoder is used to store interval size values (R _XPS ).
R _XPS =Scal(BaseTabLPS[i%μ][j], i/μ ) is configured to be obtained accordingly,
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic encoder, which is a scaling function. An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
It is configured to derive interval size values (R _LPS ; 432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously encoded symbol values,
The above arithmetic encoder is,
It is configured to determine interval size values (R _LPS ) using a probability table (ProbTabLPS) based on probability values (733, 735; 832, 842, 852; 932, 934) derived from one or more state variable values and based on coding interval sizes (R; 434; 532; 712; 812; 1362; 1460; 1512).
The above probability table describes a set of multiple probability values associated with table indices and an interval size for a given coding interval size,
The above arithmetic encoder is,
If the current probability does not belong to a set of multiple probability values and/or if the current coding interval size (R) is different from the given coding interval size, the element of the probability table (ProbTabLPS) is configured to be scaled to obtain the interval size value (R _LPS ).
The above arithmetic encoder is,
An arithmetic encoder configured to perform arithmetic encoding of one or more symbols using said interval size values (R _LPS ). In paragraph 88,
The above arithmetic encoder, the interval size value,
- Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
- using a second scaling of the result of said first scaling, depending on whether the element associated with the current probability value is included in the set of said plurality of probability values associated with the table indices,
An arithmetic encoder configured to obtain. In paragraph 89,
The remainder of the division between the first size value and the probability index, which describes the expansion of the base lookup table in the first direction, determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the second scaling, and/or
An arithmetic encoder in which the above coding interval size (R) determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In paragraph 89,
The above arithmetic encoder is,
Interval size value (R _XPS ),

It is configured to be obtained accordingly,
Here, i is the table index associated with the probability information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. In paragraph 88,
The above arithmetic encoder, the interval size value,
- using a first scaling of a selected element of the probability table, depending on whether the element associated with the current probability value is included in said probability value,
- Using a second scaling of the result of the first scaling, depending on the coding interval size (R),
An arithmetic encoder configured to obtain. In paragraph 92,
The remainder of the division between the first size value and the probability index, which describes the expansion of the probability table, determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the first scaling, and/or
An arithmetic encoder in which the above coding interval size (R) determines a multiplicative scaling factor (Qr ₂ (R)) of the second scaling. In paragraph 92,
The above arithmetic encoder is,
Interval size value (R _XPS ),

It is configured to be obtained accordingly,
Here, i is the table index associated with the probability information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic encoder, which is a scaling function. An arithmetic decoder (50; 500; 1620; 1720) for decoding a plurality of symbols (24'', 520; 1622; 1722) having symbol values,
The above arithmetic decoder is,
It is configured to derive interval size values (R _LPS ; 432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously decoded symbol values,
The above arithmetic decoder is,
It is configured to determine the interval size value (R _LPS ) using the base lookup table (Base TabLPS).
The above arithmetic decoder is,
The interval size value (R LPS) is determined such that if the probability index (i; 852; 1332; 1432; 1532) obtained based on the one or more state variable values is within a first range, the determined interval size value is equal to an element of the base lookup table or a rounded version of an element of the base lookup table, and if the probability index is within a _second range, the determined interval size value is obtained using scaling and rounding of the elements of the base lookup table.
The above arithmetic decoder is,
An arithmetic decoder configured to perform arithmetic decoding of one or more symbols using the interval size value (R _LPS ). In paragraph 95,
The above arithmetic decoder is,
An arithmetic decoder configured to determine the interval size value (R _LPS ) such that the determined interval size value becomes a right-shifted version of an element of the base lookup table if the probability index is within the second range. In paragraph 95,
The above probability index is,
An arithmetic decoder that determines whether an element of the lookup table is provided as the interval size value (R _LPS ), or whether an element of the lookup table is scaled and rounded to obtain the interval size value (R _LPS ). In paragraph 95,
An arithmetic decoder, wherein a division residual of a division between a first magnitude value and a probability index, which describes an extension of a base lookup table in a first direction, and an interval magnitude index, which is obtained based on coding interval magnitude information, determines which element of the base lookup table is used to obtain the interval magnitude value. In paragraph 95,
The above arithmetic decoder, the interval size value (R _XPS )
R _XPS =Scal(BaseTabLPS[i%μ][j], i/μ ) is configured to be obtained accordingly,
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic decoder that is a scaling function. An arithmetic decoder (50; 500; 1620; 1720) for decoding a plurality of symbols (24'', 520; 1622; 1722) having symbol values,
The above arithmetic decoder is,
It is configured to derive interval size values (R _LPS ; 432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously decoded symbol values,
The above arithmetic decoder is,
It is configured to determine the interval size value (R _LPS ) using a probability table (ProbTabLPS) based on the probability value derived from one or more state variable values and based on the coding interval size (R; 434; 532; 712; 812; 1362; 1460; 1512).
The above probability table describes a set of multiple probability values associated with table indices and an interval size for a given coding interval size,
The above arithmetic decoder is,
If the current probability does not belong to a set of multiple probability values and/or if the current coding interval size (R) is different from the given coding interval size, the element of the probability table (ProbTabLPS) is configured to be scaled to obtain the interval size value (R _LPS ).
The above arithmetic decoder is,
An arithmetic decoder configured to perform arithmetic decoding of one or more symbols using the interval size value (R _LPS ). In Article 100,
The above arithmetic decoder, the interval size value,
- Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
- using a second scaling of the result of said first scaling, depending on whether the element associated with the current probability value is included in the set of said plurality of probability values associated with the table indices,
An arithmetic decoder configured to obtain. In Article 101,
The remainder of the division between the first size value and the probability index, which describes the expansion of the base lookup table in the first direction, determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the second scaling, and/or
An arithmetic decoder in which the above coding interval size (R) determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In Article 101,
The above arithmetic decoder is,
Interval size value (R _XPS ),

It is configured to be obtained accordingly,
Here, i is the table index associated with the probability information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 100,
The above arithmetic decoder, the interval size value,
- using a first scaling of a selected element of the probability table, depending on whether the element associated with the current probability value is included in said probability value,
- Using a second scaling of the result of the first scaling, depending on the coding interval size (R),
An arithmetic decoder configured to obtain. In Article 104,
The remainder of the division between the first size value and the probability index, which describes the expansion of the probability table, determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the first scaling, and/or
An arithmetic decoder in which the above coding interval size (R) determines a multiplicative scaling factor (Qr ₂ (R)) of the second scaling. In Article 104,
The above arithmetic decoder is,
Interval size value (R _XPS ),

It is configured to be obtained accordingly,
Here, i is the table index associated with the probability information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. An arithmetic encoder (34; 400) for encoding a plurality of symbols (24'', 410) having symbol values,
The above arithmetic encoder is,
configured to determine a combined state variable value representing statistics of a plurality of previously encoded symbol values,
The above arithmetic encoder is,
A subinterval width value for arithmetic encoding of a symbol value to be encoded from the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values. ; 432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762),
A one-dimensional lookup table containing probability values for different value intervals of a value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, ) entries are mapped to probability values (p _i ^k ; p ^k ; p _LPS ; Q _p (p _LPS )),
Coding interval size information (R; 434; 532; 712; 812; 1362; 1460; 1512) describing the size of the coding interval of the arithmetic encoding prior to the arithmetic encoding of the symbol value to be encoded, and the quantization level (( ; ; 762; 862) and quantized.
configured to determine by determining the product between the above probability value and the above quantization level,
The above arithmetic encoder is an arithmetic encoder configured to perform state variable value update depending on the symbol value to be encoded. In Article 107,
The above arithmetic encoder is,
An arithmetic encoder configured to derive a combined state variable value based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values having different adaptation time constants. In Article 108,
The above arithmetic encoder is,
An arithmetic encoder configured to determine a weighted sum of state variable values to obtain the combined state variable values. In Article 108,
The above arithmetic encoder is,
In order to obtain the above combined state variable values,
The state variable values and the weight values associated with the state variable values ( ) is configured to determine the sum of the rounded values obtained by rounding the product of the two. In Article 108,
The above arithmetic encoder is,
The above combined state variable values s _k

It is configured to decide accordingly,
Here, s ^k _i is the state variable value,
N is the number of state variable values considered,
. is the floor operator,
d ^k _i is an arithmetic encoder, which is a weight value associated with the state variable value. In Article 108,
The above arithmetic encoder is,
When performing the above state variable value update, the multiple variable state values cast

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
Updated To avoid going beyond the predetermined value range,
or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being encoded is 1 And,
If the symbol being encoded is 0 In, arithmetic encoder. In Article 112,
The above arithmetic encoder is,
By table lookup or calculation An arithmetic encoder configured to induce . In Article 107,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In Article 107,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In Article 107,
The above arithmetic encoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic encoder, which has one or more weights. In Article 107,
The above arithmetic encoder is,
An arithmetic encoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In Article 107,
The above arithmetic encoder is,
Quantizing the coding interval size information R is configured to perform by,
Here , and is an arithmetic encoder with integer-valued parameters. In Article 107,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. In Article 107,
An arithmetic encoder wherein different value intervals of the value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, are sized identically. In Article 120,
The entries in the above one-dimensional lookup table are,
An arithmetic encoder that monotonically decreases at a decreasing rate as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. An arithmetic decoder for decoding multiple symbols having symbol values,
The above arithmetic decoder is,
It is configured to derive interval size information for arithmetic decoding of one or more to-be-decoded symbol values based on a plurality of state variable values representing statistics of a plurality of previously decoded symbol values having different adaptation time constants,
The above arithmetic decoder is,
To obtain interval size information describing the interval size for arithmetic decoding of one or more symbols to be decoded,
Mapping the first state variable value, or a scaled version and/or a rounded version of the first state variable value, using a lookup table (LUT1),
An arithmetic decoder configured to map a second state variable value, or a scaled version and/or a rounded version of the second state variable value, using a lookup table (LUT1). In paragraph 122,
The above arithmetic decoder is,
configured to map the first state variable value, or a scaled version and/or a rounded version of the first state variable value, to a first probability value using the lookup table,
The above arithmetic decoder is,
configured to map the second state variable value, or a scaled version and/or a rounded version of the second state variable value, to a second probability value using the lookup table,
An arithmetic decoder, wherein the arithmetic decoder is configured to obtain a combined probability value using the first probability value and the second probability value. In Article 123,
The above arithmetic decoder is,
If the decoded symbol has a first value, the state variable value is changed in the first direction, and if the decoded symbol has a second value different from the first value, the state variable value is changed in the second direction.
An arithmetic decoder, wherein the arithmetic decoder is configured to determine which entry of a lookup table is to be evaluated based on the absolute value of an individual state variable value. In Article 124,
The above arithmetic decoder is,
If the first state variable value has the first sign, the first probability value is configured to be set to a value provided by the lookup table,
The above arithmetic decoder is,
An arithmetic decoder configured to set the first probability value to a value obtained by subtracting a value provided by the lookup table from a predetermined value if the first state variable value has a second sign. In paragraph 122,
The above arithmetic decoder is,
Two or more probability values p ^k _i
It is configured to decide accordingly,
LUT1 is a lookup table containing probability values;
. is the floor operator,
s ^k _i is the i-th state variable value,
An arithmetic decoder, where a ^k _i is a weighting value associated with the i-th state variable value. In paragraph 122,
The above arithmetic decoder is,
Two or more probability values p ^k _i
It is configured to decide accordingly,
LUT1 is a lookup table containing probability values;
. is the floor operator,
s ^k _i is the i-th state variable value,
An arithmetic decoder, where a ^k _i is a weighting value associated with the i-th state variable value. In Article 123,
The above arithmetic decoder is,

Accordingly, it is configured to obtain a combined probability value p ^k based on a plurality of probability values p ^k _i ,
N is the number of probability values considered,
arithmetic decoder, where b ^k _i are weights. In paragraph 122,
The above arithmetic decoder is,
configured to map the first state variable value, or a scaled version and/or a rounded version of the first state variable value, to a first subinterval width value (R*p k 1 ) using a two-dimensional lookup table, the entries of which depend on the first state variable value and are addressed depending on coding interval size information describing the size of a coding interval of arithmetic decoding prior to decoding of a ^symbol _;
The above arithmetic decoder is,
configured to map the second state variable value, or a scaled version and/or a rounded version of the second state variable value, to a second subinterval width value (R*p k 2 ) using a two-dimensional lookup table whose entries are addressed depending on the second state variable value and depending on coding interval size information describing the size of a coding ^interval of arithmetic decoding prior to decoding of a symbol _;
The above arithmetic decoder is,
An arithmetic decoder configured to obtain a combined sub-interval width value using the first sub-interval width value and the second sub-interval width value. In Article 129,
The above two-dimensional lookup table is,
a first 1-dimensional vector entry comprising probability values for different value intervals of the value domain for the first state variable value and the second state variable value, or for scaled versions and/or rounded versions of the first state variable value and the second state variable value, and
An arithmetic decoder, which can be expressed as a dyadic product between second 1-dimensional vector entries including quantization levels for the above coding interval size information. In Article 129,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the base lookup table (Base TabLPS),
A first group of elements of the above two-dimensional lookup table are identical to elements of the above base lookup table or are rounded versions of elements of the above base lookup table,
An arithmetic decoder, wherein the second group of elements of the two-dimensional lookup table are scaled and rounded versions of the elements of the base lookup table. In Article 131,
An arithmetic decoder, wherein the second group of elements of the two-dimensional lookup table are right-shifted versions of the elements of the base lookup table. In Article 131,
A probability index based on one of the above state variable values determines whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated,
The first range of probability indices is associated with the elements of the first group of elements,
An arithmetic decoder, wherein the second range of the above probability indices is associated with elements of a second group of elements. In Article 133,
An arithmetic decoder, wherein a division residual of a division between a first size value and a probability index, which describes an extension of the base lookup table in the first direction, and an interval size index, which is obtained based on coding interval size information, determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table. In Article 129,
The above arithmetic decoder is,
It is configured to obtain elements of the above two-dimensional lookup table as follows:
RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j], i/μ ),
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 129,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the probability table (probTabLPS),
The above probability table describes the interval size for a set of multiple probability values associated with table indices and for a given coding interval size,
An arithmetic decoder, wherein elements of a two-dimensional lookup table for probability values not included in the set of the plurality of probability values or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling. In Article 136,
The elements of the above two-dimensional lookup table are:
- Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
- Using a second scaling of the result of the first scaling, depending on whether the element associated with the current probability value is included in the set of said probability values,
Obtained, arithmetic decoder. In Article 137,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
An integer division result of the division between said probability index and said first magnitude value, which represents a current probability value, determines a scaling factor used in said second scaling, and/or
An arithmetic decoder, wherein the above coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In Article 136,
The above arithmetic decoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 136,
The elements of the above two-dimensional lookup table are:
An arithmetic decoder obtained by using a first scaling of a selected element of the probability table depending on whether the element associated with the current probability value is included in the set of probability values, and a second scaling of a result of the first scaling depending on the coding interval size (R). In Article 140,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between said probability index and said first magnitude value, which represents the current probability value, determines the scaling factor used in said first scaling, and/or
An arithmetic decoder in which the above coding interval size (R) determines the multiplication scaling factor (Qr ₂ (R)) of the second scaling. In Article 136,
The above arithmetic decoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. In paragraph 122,
The above arithmetic decoder is,
From the first state variable value and the second state variable value, or the scaled version and/or the rounded version of the first state variable value and the second state variable value, first and second subinterval width values (R*p ^k ),
Mapping the first and second state variable values, or the scaled and/or rounded versions of the first and second state variable values, to the first and second probability values using a one-dimensional lookup table (LUT4) entry containing probability values for different value intervals of the value domain for the first state variable value and the second state variable value, or the scaled and/or rounded versions of the first state variable value and the second state variable value,
The coding interval size information, which describes the size of the coding interval of the arithmetic encoding prior to encoding of the symbol, is quantized into a quantization level.
In one aspect, the product of the first and second probability values and the quantization level is determined,
An arithmetic decoder configured to calculate, respectively, a combined sub-interval width value by using the first sub-interval width value and the second sub-interval width value. In Article 143,
The above arithmetic decoder is,
An arithmetic decoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In Article 143,
The above arithmetic decoder is,
Coding interval size information Quantizing it is configured to perform by,
Here , and is a parameterized arithmetic decoder. In Article 143,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases as the first state variable value and the second state variable value, or the scaled version and/or rounded version of the first state variable value and the second state variable value, increases. In Article 143,
An arithmetic decoder wherein different value intervals of the value domain for the first state variable value and the second state variable value, or for scaled versions and/or rounded versions of the first state variable value and the second state variable value, are sized identically. In Article 147,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases at a decreasing rate as the first state variable value and the second state variable value, or the scaled version and/or rounded version of the first state variable value and the second state variable value, increases. An arithmetic decoder (50; 500: 1620; 1720) for decoding a plurality of symbols (24'', 520; 1622; 1722) having symbol values,
The above arithmetic decoder is,
Based on a plurality of state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously decoded symbol values having different adaptation time constants, interval size information (432; 534; 620; 720; 820; 820; 1020; 1084; 1120; 1320; 1420; 1520; 1662; 1762) for arithmetic decoding of one or more symbol values to be decoded is derived,
The above arithmetic decoder is,
Based on the above multiple state variable values, it is configured to derive a combined state variable value,
The above arithmetic decoder obtains interval size information describing an interval size for the arithmetic decoding of one or more symbols to be decoded.
An arithmetic decoder configured to map combined state variable values, or scaled versions and/or rounded versions of said combined state variable values, using a lookup table. In Article 149,
The above arithmetic decoder is,
An arithmetic decoder configured to determine a weighted sum of state variable values to obtain the combined state variable values. In Article 149,
The above arithmetic decoder is,
In order to obtain the above combined state variable values,
The state variable values and the weight values associated with the state variable values ( ) is configured to determine the sum of the rounded values obtained by rounding the product of the two. In Article 149,
The above arithmetic decoder is,
The above combined state variable values s _k

It is configured to decide accordingly,
Here, s ^k _i is the state variable value,
N is the number of state variable values considered,
. is the floor operator,
d ^k _i is an arithmetic decoder, which is a weight value associated with the state variable value. In Article 149,
The above arithmetic decoder is,
If the decoded symbol has a first value, the state variable value is changed in the first direction, and if the decoded symbol has a second value different from the first value, the state variable value is changed in the second direction.
An arithmetic decoder, wherein the arithmetic decoder is configured to determine which entry of the lookup table is to be evaluated based on the absolute value of the associated state variable values. In Article 153,
The above arithmetic decoder is,
If the above combined state variable value has a first sign, the probability value describing the symbol probability is set to a value provided by the lookup table,
The above arithmetic decoder is,
An arithmetic decoder configured to set the probability value to a value obtained by subtracting a value provided by the lookup table from a predetermined value if the combined state variable value has a second sign. In Article 149,
The above arithmetic decoder is,
A combined probability value p _k that describes the symbol probability

It is configured to decide accordingly,
Here, LUT2 is a lookup table containing probability values,
. is the floor operator;
s _k is the combined variable value;
a _k is an arithmetic decoder, which is a weight associated with the combined state variable values. In Article 149,
The above arithmetic decoder is,
The combined probability value p _k , which describes the symbol probability,

It is configured to decide accordingly,
Here, LUT2 is a lookup table containing probability values,
. is the floor operator,
s _k is the combined state variable value,
a _k is an arithmetic decoder, which is a weight associated with the combined state variable values. In Article 149,
The above arithmetic decoder is,
Subinterval width cast

It is configured to decide accordingly,
Here LUT3 is a 2D lookup table,
. is the floor operator,
s _k is the combined state variable value,
a _k is the weight associated with the above combined state variable values,
R is the interval size,
Arithmetic decoder, where the quantized values are interval sizes. In Article 149,
The above arithmetic decoder is,
An arithmetic decoder configured to map the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, to subinterval width values using a two-dimensional lookup table, the entries of which depend on the combined state variable values and are addressed depending on coding interval size information describing the size of a coding interval of the arithmetic decoding prior to decoding of a symbol. In Article 158,
The above two-dimensional lookup table is,
a first 1-dimensional vector entry comprising probability values for different value intervals of the value domain for the combined state variable values, or for scaled and/or rounded versions of the combined state variable values, and
An arithmetic decoder, which can be expressed as a dyadic product between second 1-dimensional vector entries including quantization levels for the above coding interval size information. In Article 158,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the base lookup table (Base TabLPS),
A first group of elements of the above two-dimensional lookup table are identical to elements of the above base lookup table or are rounded versions of elements of the above base lookup table,
An arithmetic decoder, wherein the second group of elements of the two-dimensional lookup table are scaled and rounded versions of the elements of the base lookup table. In Article 160,
An arithmetic decoder, wherein the second group of elements of the two-dimensional lookup table are right-shifted versions of the elements of the base lookup table. In Article 160,
A probability index, derived directly from the combined state variable values or using a combined probability value based on the combined state variable values, determines whether an element of a first group of elements of the two-dimensional lookup table or an element of a second group of elements of the two-dimensional lookup table is evaluated,
The first range of probability indices is associated with the elements of the first group of elements,
An arithmetic decoder, wherein the second range of the above probability indices is associated with elements of a second group of elements. In paragraph 162,
An arithmetic decoder, wherein a division residual of a division between a first size value and a probability index, which describes an extension of the base lookup table in the first direction, and an interval size index, which is obtained based on coding interval size information, determines which element of the base lookup table is used to obtain an element of the two-dimensional lookup table. In Article 158,
The above arithmetic decoder is,
It is configured to obtain elements of a two-dimensional lookup table (RangeTabLPS) as follows:
RangeTabLPS[i][j]=Scal(BaseTabLPS[i%μ][j], i/μ ),
Here, BaseTabLPS is a base lookup table of dimension μ x λ,
μ describes the extension of the base lookup table in the first direction,
λ describes the second dimension of the base lookup table,
i is the table index associated with the probability information,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is a division operation,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 158,
The elements of the above two-dimensional lookup table (RangeTabLPS) are defined based on the probability table (probTabLPS),
The above probability table describes the interval size for a set of multiple probability values associated with table indices and for a given coding interval size,
An arithmetic decoder, wherein elements of a two-dimensional lookup table for probability values not included in the set of the plurality of probability values or for coding interval sizes different from the given coding interval size are derived from the probability table using scaling. In Article 165,
The elements of the above two-dimensional lookup table are:
Using a first scaling of the selected elements of the probability table depending on the coding interval size (R), and
An arithmetic decoder obtained by using a second scaling of the result of said first scaling, depending on whether the element associated with the current probability value is included in the set of said probability values. In Article 166,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
An integer division result of the division between said probability index and said first magnitude value, which represents a current probability value, determines a scaling factor used in said second scaling, and/or
An arithmetic decoder, wherein the above coding interval size determines a multiplicative scaling factor (Qr ₂ (R)) of the first scaling. In Article 165,
The above arithmetic decoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 165,
The elements of the above two-dimensional lookup table are:
An arithmetic decoder obtained by using a first scaling of a selected element of the probability table depending on whether the element associated with the current probability value is included in the set of probability values, and a second scaling of a result of the first scaling depending on the coding interval size (R). In Article 169,
A division remainder between a probability index representing a current probability value and a first magnitude value describing an extension of a probability table determines which element of said probability table is scaled in said first scaling, and/or
The integer division result of the division between the above probability index and the first size value determines the scaling factor used in the first scaling, and/or
An arithmetic decoder in which the above coding interval size (R) determines the multiplication scaling factor (Qr ₂ (R)) of the second scaling. In Article 165,
The above arithmetic decoder is,
Elements of the above two-dimensional lookup table cast,

It is configured to be obtained accordingly,
Here, i is the table index associated with an individual probability value,
j is the table index associated with the interval size information,
% is the remainder operation of division,
/ is the division operation,
probTabLPS[] is a probability table,
μ is the number of elements in the above probability table,
R is the interval size,
Qr ₂ (R) is a scaling factor that depends on R,
Scal(x, y) is an arithmetic decoder that is a scaling function. In Article 149,
The above arithmetic decoder is,
From the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, a subinterval width value,
Mapping the combined state variable value, or a scaled version and/or a rounded version of the combined state variable value, to a combined probability value using a one-dimensional lookup table (LUT4) entry containing probability values for different value intervals of the value domain for the combined state variable value, or the scaled version and/or the rounded version of the combined state variable value,
The coding interval size information, which describes the size of the coding interval of the arithmetic encoding prior to encoding of the symbol, is quantized into a quantization level.
An arithmetic decoder configured to calculate by determining a product of the combined probability value and the quantization level. In Article 168,
The above arithmetic decoder is,
An arithmetic decoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In paragraph 172,
The above arithmetic decoder is,
Coding interval size information Quantizing it is configured to perform by,
Here , and An arithmetic decoder with integer-valued parameters. In paragraph 172,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases as the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, increase. In paragraph 172,
An arithmetic decoder wherein different value intervals of the value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, are sized identically. In paragraph 176,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases at a decreasing rate as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. In Article 149,
The above lookup table is an arithmetic decoder that specifies exponential decay. In Article 149,
The above arithmetic decoder is,
Multiple variable state values cast

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
Updated To avoid going beyond the predetermined value range,
or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being encoded is 1 And,
If the symbol being encoded is 0 In, arithmetic decoder. In Article 179,
The above arithmetic decoder is,
By table lookup or calculation An arithmetic decoder configured to derive . In Article 149,
The above arithmetic decoder is,
Multiple variable state values cast

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
In, arithmetic decoder. An arithmetic decoder (50; 500; 1620; 1720) for decoding a plurality of symbols (24'', 520; 1622; 1722) having symbol values,
The above arithmetic decoder is,
configured to determine one or more state variable values (642, 644; 710; 810; 910; 1010a, 1010b; 1082a, 1082b; 1110; 1210; 1310; 1410; 1510; 1632, 1642; 1732, 1742) representing statistics of a plurality of previously decoded symbol values,
The above arithmetic decoder is,
It is configured to derive interval size information for arithmetic decoding of one or more symbol values to be decoded based on one or more state variable values representing statistics of a plurality of previously decoded symbol values,
The above arithmetic decoder is,
An arithmetic decoder configured to update the value of a first state variable based on a decoded symbol and using a lookup table. In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to update the value of a second state variable based on the decoded symbol and using a lookup table (A). In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to update the first state variable value and the second state variable value using different adaptation time constants. In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to selectively increment or decrement a previous state variable value by a value determined using the lookup table, depending on whether a decoded symbol has a first value or a second value different from the first value. In Article 182,
The above arithmetic decoder is,
If the decoded symbol has a first value, the previous state variable value is configured to be increased by a relatively larger value when the previous state variable value is negative compared to when the previous state variable value is positive,
The above arithmetic decoder is,
An arithmetic decoder configured to decrease the previous state variable value by a relatively larger value when the previous state variable value is positive compared to when the previous state variable value is negative, if the decoded symbol has a second value different from the first value. In Article 182,
The above arithmetic decoder is,
If the decoded symbol has a first value, the index of an entry of the lookup table to be evaluated when updating the first state variable value is determined based on a sum of a predetermined offset value (z) and a previously computed first state variable value, or a scaled version and/or a rounded version of the previously computed first state variable value,
The above arithmetic decoder is,
An arithmetic decoder configured to determine an index of an entry of the lookup table to be evaluated when updating the first state variable value, depending on a sum of a predetermined offset value (z) and an inverted version of the previously computed first state variable value, or a scaled version and/or a rounded version of the inverted version of the previously computed first state variable value, if the decoded symbol has a second value. In Article 182,
The above arithmetic decoder is,
If the decoded symbol has a first value, the index of an entry of the lookup table to be evaluated when updating the second state variable value is determined based on a sum of a predetermined offset value (z) and a previously computed second state variable value, or a scaled version and/or a rounded version of the previously computed second state variable value,
The above arithmetic decoder is,
An arithmetic decoder configured to determine an index of an entry of the lookup table to be evaluated when updating the second state variable value, depending on a sum of a predetermined offset value (z) and an inverted version of the previously computed second state variable value, or a scaled version and/or a rounded version of the inverted version of the previously computed second state variable value, if the decoded symbol has a second value. In Article 182,
The above arithmetic decoder is,
When determining an index of an entry of the lookup table to be evaluated when updating the first state variable value, a first scaling value is configured to be applied to scale the previously calculated first state variable value,
The arithmetic decoder is configured to apply a second scaling value to scale a previously computed second state variable value when determining an index of an entry of the lookup table to be evaluated when updating the second state variable value,
An arithmetic decoder wherein the first scaling value is different from the second scaling value. In Article 182,
The above arithmetic decoder is,
When updating the first state variable value, the value returned by the evaluation of the lookup table is configured to be scaled using the first scaling value,
The above arithmetic decoder is,
When updating the value of the second state variable, the value returned by the evaluation of the lookup table is configured to be scaled using the second scaling value,
An arithmetic decoder wherein the first scaling value is different from the second scaling value. In Article 182,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 182,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 182,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 182,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 191,
An arithmetic decoder in which the entries of A monotonically decrease as the lookup table index increases. In Article 191,
A is
Updated To avoid going beyond the predetermined value range,
or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being decoded is 1 And,
If the symbol being decoded is 0 In, arithmetic decoder. In Article 182,
The last entry in the above lookup table is an arithmetic decoder equal to zero. In Article 191,
A is
In, arithmetic decoder. In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to apply a clipping operation to the updated state variable values so as to keep the updated state variable values and the clipped state variable values within a predetermined range of values. In Article 199,
The above arithmetic decoder is,
Clipping operation

is configured to apply to the updated state variable values according to
Here Is is the maximum allowable value for ,
Is The minimum allowable value for an arithmetic decoder. In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to apply different scaling values for different contexts. In Article 182,
The above arithmetic decoder is,
An arithmetic decoder configured to obtain interval size information as specified in Article 122. An arithmetic decoder (50; 500; 1622; 1722) for decoding a plurality of symbols (24'', 520; 1620; 1720) having symbol values,
The above arithmetic decoder is,
configured to determine a combined state variable value representing statistics of a plurality of previously decoded symbol values,
The above arithmetic decoder is,
A subinterval width value for arithmetic decoding of a symbol value to be decoded from the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values. )second,
A one-dimensional lookup table containing probability values for different value intervals of a value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, ) entries are mapped to combined probability values,
The coding interval size information describing the size of the coding interval of the arithmetic encoding prior to the arithmetic decoding of the symbol value to be encoded is the quantization level ( ) and quantized into
configured to determine by determining the product between the above probability value and the above quantization level,
The above arithmetic decoder is an arithmetic decoder configured to perform state variable value updates depending on the symbol value to be decoded. In Article 203,
The above arithmetic decoder is,
An arithmetic decoder configured to derive a combined state variable value based on a plurality of state variable values representing statistics of a plurality of previously decoded symbol values having different adaptation time constants. In paragraph 204,
The above arithmetic decoder is,
An arithmetic decoder configured to determine a weighted sum of state variable values to obtain the combined state variable values. In paragraph 204,
The above arithmetic decoder is,
In order to obtain the above combined state variable values,
The state variable values and the weight values associated with the state variable values ( ) is configured to determine the sum of the rounded values obtained by rounding the product of the two. In paragraph 204,
The above arithmetic decoder is,
The above combined state variable values s _k

It is configured to decide accordingly,
Here, s ^k _i is the state variable value,
N is the number of state variable values considered,
. is the floor operator,
d ^k _i is an arithmetic decoder, which is a weight value associated with the state variable value. In paragraph 204,
The above arithmetic decoder is,
When performing the above state variable value update, the above multiple variable state values cast,

It is configured to update accordingly,
Here, z is a predetermined offset value,
is one or more weights,
is one or more weights,
A is
Updated To avoid going beyond the predetermined value range,
or, having a deviation by zero setting or size reduction only for one or more extreme values of the argument,
Here , , , and is a predetermined parameter,
If the symbol being encoded is 1 And,
If the symbol being encoded is 0 In, arithmetic decoder. In Article 208,
The above arithmetic decoder is,
By table lookup or calculation An arithmetic decoder configured to derive . In Article 203,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 203,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 203,
The above arithmetic decoder is,
One or more updated state variable values cast

It is configured to decide accordingly,
Here, A is a lookup table,
z is a predetermined offset value,
is one or more weights,
An arithmetic decoder, which has one or more weights. In Article 203,
The above arithmetic decoder is,
An arithmetic decoder configured to quantize the coding interval size information by applying a logical right transition to the coding interval size information. In Article 203,
The above arithmetic decoder is,
Quantizing the coding interval size information R

is configured to perform by,
Here , and An arithmetic decoder with integer-valued parameters. In Article 203,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases as the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, increase. In Article 203,
An arithmetic decoder wherein different value intervals of the value domain for the combined state variable values, or scaled versions and/or rounded versions of the combined state variable values, are sized identically. In Article 216,
The entries in the above one-dimensional lookup table are,
An arithmetic decoder that monotonically decreases at a decreasing rate as the combined state variable values, or a scaled version and/or a rounded version of the combined state variable values, increase. As a video encoder (10),
The above video encoder is configured to encode a plurality of video frames (12),
The above video encoder,
A video encoder (10) comprising an arithmetic encoder (34; 400) for providing an encoded binary sequence (420) based on a sequence (410) of binary values representing video content, according to any one of claims 1 to 83. As a video decoder (20; 1600; 1700),
The above video decoder is configured to decode a plurality of video frames (12'),
The above video decoder,
A video decoder (20; 1600; 1700) comprising an arithmetic decoder (50; 500; 1620; 1720) for providing a decoded binary sequence (24'', 520; 1622; 1722) based on an encoded representation (14; 510; 1610; 1710) of the binary sequence according to any one of claims 122, 203 or 95. A method for encoding multiple symbols having symbol values,
The above method,
A step of deriving interval size information for arithmetic encoding of one or more symbol values to be encoded, based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values having different adaptation time constants,
The above method,
To obtain interval size information describing the interval size for arithmetic encoding of one or more symbols to be encoded,
Mapping the first state variable value, or a scaled version and/or a rounded version of the first state variable value, using a lookup table (LUT1),
An encoding method comprising the step of mapping a second state variable value, or a scaled version and/or a rounded version of the second state variable value, using a lookup table (LUT1). A method for encoding multiple symbols having symbol values,
The above method,
A step of deriving interval size information for arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values having different adaptation time constants,
The above method,
A step of deriving a combined state variable value based on the above plurality of state variable values,
The above method,
To obtain interval size information describing the interval size for the arithmetic encoding of one or more symbols to be encoded,
An encoding method comprising the step of mapping combined state variable values, or scaled versions and/or rounded versions of said combined state variable values, using a lookup table. A method for encoding multiple symbols having symbol values,
The above method,
Comprising the step of determining one or more state variable values representing statistics of a plurality of previously encoded symbol values,
The above method,
A step of deriving interval size information for arithmetic encoding of one or more symbol values to be encoded based on one or more state variable values representing statistics of a plurality of previously encoded symbol values,
The above method,
An encoding method, comprising the step of updating a first state variable value using a lookup table and depending on a symbol to be encoded. A method for decoding multiple symbols having symbol values,
The above method,
A step of deriving interval size information for arithmetic decoding of one or more to-be-decoded symbol values based on a plurality of state variable values representing statistics of a plurality of previously decoded symbol values having different adaptation time constants,
The above method,
To obtain interval size information describing the interval size for arithmetic decoding of one or more symbols to be decoded,
Mapping the first state variable value, or a scaled version and/or a rounded version of the first state variable value, using a lookup table (LUT1),
A decoding method comprising the step of mapping a second state variable value, or a scaled version and/or a rounded version of the second state variable value, using a lookup table (LUT1). A method for decoding multiple symbols having symbol values,
The above method,
A step of deriving interval size information for arithmetic decoding of one or more symbol values to be decoded based on a plurality of state variable values representing statistics of a plurality of previously decoded symbol values having different adaptation time constants,
The above method,
A step of deriving a combined state variable value based on the above plurality of state variable values,
The above method,
To obtain interval size information describing the interval size for the arithmetic decoding of one or more symbols to be decoded,
A decoding method, comprising the step of mapping combined state variable values, or scaled versions and/or rounded versions of said combined state variable values, using a lookup table. A method for decoding multiple symbols having symbol values,
The above method,
Comprising the step of determining one or more state variable values representing statistics of a plurality of previously decoded symbol values,
The above method,
A step of deriving interval size information for arithmetic decoding of one or more symbol values to be decoded based on one or more state variable values representing statistics of a plurality of previously decoded symbol values,
The above method,
A decoding method, comprising the step of updating a first state variable value based on a decoded symbol and using a lookup table. An encoding method performed by an encoder according to any one of claims 1 to 94 or 107 to 121. A decoding method performed by a decoder according to any one of claims 95 to 106 or 122 to 217. A computer-readable storage medium storing a computer program for performing a method according to any one of claims 220 or 221 or 222 or 223 or 224 or 225 when the computer program is executed on a computer. A method for encoding multiple symbols having symbol values,
The above method,
A step of deriving an interval size value (R _LPS ) for arithmetic encoding of one or more symbol values to be encoded based on one or more state variable values (s _i ^k ) representing statistics of a plurality of previously encoded symbol values,
The above method,
A step of determining the interval size value (R _LPS ) using a base lookup table (Base TabLPS),
The above method,
A step of determining an interval size value (R LPS) such that if the probability index (i) obtained based on the one or more state variable values is within a first range, the determined interval size value is equal to an element of the base lookup table or a rounded version of an element of the base lookup table, and if the probability index is within a second range, the determined interval size value is obtained using scaling and rounding of the _elements of the base lookup table,
The above method,
An encoding method comprising the step of performing an arithmetic encoding of one or more symbols using the interval size value (R _LPS ). A method for encoding multiple symbols having symbol values,
The above method,
A step of deriving an interval size value (R _LPS ) for arithmetic encoding of one or more symbol values to be encoded, based on one or more state variable values representing statistics of a plurality of previously encoded symbol values,
The above method,
A step of determining an interval size value (R _LPS ) using a probability table (ProbTabLPS) based on a probability value derived from one or more state variable values and based on the coding interval size (R),
The above probability table describes a set of multiple probability values associated with table indices and an interval size for a given coding interval size,
The above method,
If the current probability does not belong to a set of multiple probability values and/or if the current coding interval size (R) is different from the given coding interval size, a step of scaling an element of the probability table (ProbTabLPS) to obtain the interval size value (R _LPS ) is included.
The above method,
An encoding method comprising the step of performing an arithmetic encoding of one or more symbols using the interval size value (R _LPS ). A method for decoding multiple symbols having symbol values,
The above method,
A step of deriving an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values representing statistics of a plurality of previously decoded symbol values,
The above method,
A step of determining the interval size value (R _LPS ) using a base lookup table (Base TabLPS),
The above method,
A step of determining an interval size value (R LPS) such that if the probability index (i) obtained based on the one or more state variable values is within a first range, the determined interval size value is equal to an element of the base lookup table or a rounded version of an element of the base lookup table, and if the probability index is within a second range, the determined interval size value is obtained using scaling and rounding of the _elements of the base lookup table,
The above method,
A decoding method, comprising the step of performing arithmetic decoding of one or more symbols using the interval size value (R _LPS ). A method for decoding multiple symbols having symbol values,
The above method,
A step of deriving an interval size value (R _LPS ) for arithmetic decoding of one or more symbol values to be decoded, based on one or more state variable values representing statistics of a plurality of previously decoded symbol values,
The above method,
A step of determining an interval size value (R _LPS ) using a probability table (ProbTabLPS) based on a probability value derived from one or more state variable values and based on the coding interval size (R),
The above probability table describes a set of multiple probability values associated with table indices and an interval size for a given coding interval size,
The above method,
If the current probability does not belong to a set of multiple probability values and/or if the current coding interval size (R) is different from the given coding interval size, a step of scaling an element of the probability table (ProbTabLPS) to obtain the interval size value (R _LPS ) is included.
The above method,
A decoding method, comprising the step of performing arithmetic decoding of one or more symbols using the interval size value (R _LPS ). A computer-readable storage medium storing a computer program for performing a method according to any one of claims 229 or 230 or 231 or 232 when the computer program is executed on a computer. A computer-readable storage medium storing a computer program for performing the method according to claim 226 when the computer program is executed on a computer. A computer-readable storage medium storing a computer program for performing the method according to claim 227 when the computer program is executed on a computer.

Images